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[bug#38276] Fix kernel-headers path in clang
|
From: |
Carl Dong |
|
Subject: |
[bug#38276] Fix kernel-headers path in clang |
|
Date: |
Wed, 20 Nov 2019 21:28:08 +0000 |
Hi Mathieu,
I want to apologize for the confusion with that last patch I sent… That was
actually the exact opposite patch of what I intended :-)
I’ve attached the correct patch below, and some explanation:
> Plus, in general patching so heavily the sources of a package proves to
> be very hard to maintain.
These are already patches that we carry (see
gnu/packages/patches/clang-*-libc-search-path.patch), I’m simply modifying them.
> I'm not sure to understand the benefit of this patch versus hardcoding
> libc and kernel-headers path into clang at build time.
This patch _does_ hardcode libc and kernel-headers path into clang at build
time, BUT it does so in a way that also retains sane behaviour when --sysroot
is supplied to clang. Explanation from the patch:
> ++ // Check for configure-time "extra" C include directories. When
> constructing a
> ++ // toolchain, @C_EXTRA_INCLUDE_DIRS@ should be replaced with something
> like a
> ++ // colon-separated string of the include dirs of libc and kernel headers.
> ++ //
> ++ // The reason why we use this mechanism instead of C_INCLUDE_DIRS above is
> ++ // because when a user supplies clang with --sysroot, the normal
> expectation
> ++ // is that clang will detect and add the proper $SYSROOT/$MULTIARCHINCL,
> ++ // $SYSROOT/include, and $SYSROOT/usr/include to its list of search paths.
> ++ // However, if C_INCLUDE_DIRS is not empty, this function will return
> early
> ++ // and not attempt to add the aforementioned search paths, which is not
> ++ // desirable.
> ++ //
> ++ // By adding our configure-time "extra" C include directories here, after
> ++ // we've added $SYSROOT/include and $SYSROOT/usr/include, we make sure
> that IF
> ++ // --sysroot is supplied on the command line, we pick up the expected
> search
> ++ // paths in the $SYSROOT, and that they come before our configure-time
> "extra"
> ++ // C include directories.
Again, sorry for the confusion, and I look forward to hearing what you and
others think!
Cheers,
Carl Dong
-----
diff --git a/gnu/packages/llvm.scm b/gnu/packages/llvm.scm
index 33fb53d65e..9ee5062429 100644
--- a/gnu/packages/llvm.scm
+++ b/gnu/packages/llvm.scm
@@ -186,12 +186,7 @@ compiler. In LLVM this library is called
\"compiler-rt\".")
;; Find libgcc_s, crtbegin.o, and crtend.o.
(string-append "-DGCC_INSTALL_PREFIX="
- (assoc-ref %build-inputs "gcc-lib"))
-
- ;; Use a sane default include directory.
- (string-append "-DC_INCLUDE_DIRS="
- (assoc-ref %build-inputs "libc")
- "/include"))
+ (assoc-ref %build-inputs "gcc-lib")))
;; Don't use '-g' during the build to save space.
#:build-type "Release"
@@ -202,6 +197,8 @@ compiler. In LLVM this library is called \"compiler-rt\".")
(lambda* (#:key inputs #:allow-other-keys)
(let ((libc (assoc-ref inputs "libc"))
(compiler-rt (assoc-ref inputs "clang-runtime"))
+ (gcc (assoc-ref inputs "gcc"))
+ (kernel-headers (assoc-ref inputs "kernel-headers"))
(version
(string->number
,(version-major (package-version
clang-runtime)))))
@@ -221,7 +218,10 @@ compiler. In LLVM this library is called
\"compiler-rt\".")
;; Make sure libc's libdir is on the search path,
to
;; allow crt1.o & co. to be found.
(("@GLIBC_LIBDIR@")
- (string-append libc "/lib"))))
+ (string-append libc "/lib"))
+ (("@C_EXTRA_INCLUDE_DIRS@")
+ (string-append libc "/include" ":"
+ kernel-headers "/include"))))
(else
(substitute* "lib/Driver/Tools.cpp"
;; Patch the 'getLinuxDynamicLinker' function so
that
diff --git a/gnu/packages/patches/clang-3.5-libc-search-path.patch
b/gnu/packages/patches/clang-3.5-libc-search-path.patch
index 50e4480239..54fb9be7d8 100644
--- a/gnu/packages/patches/clang-3.5-libc-search-path.patch
+++ b/gnu/packages/patches/clang-3.5-libc-search-path.patch
@@ -8,7 +8,7 @@ to make sure Clang also works on non-GuixSD systems.
--- cfe-3.6.0.src/lib/Driver/ToolChains.cpp 2015-02-18 22:03:07.000000000
+0100
+++ cfe-3.6.0.src/lib/Driver/ToolChains.cpp 2015-06-19 16:37:20.459701044
+0200
-@@ -2931,6 +2931,9 @@ Linux::Linux(const Driver &D, const llvm
+@@ -3040,6 +3040,9 @@
Linker = GetLinkerPath();
@@ -18,7 +18,7 @@ to make sure Clang also works on non-GuixSD systems.
Distro Distro = DetectDistro(Arch);
if (IsOpenSUSE(Distro) || IsUbuntu(Distro)) {
-@@ -2973,6 +2976,7 @@ Linux::Linux(const Driver &D, const llvm
+@@ -3082,6 +3085,7 @@
if (IsOpenSUSE(Distro))
ExtraOpts.push_back("--enable-new-dtags");
@@ -26,41 +26,49 @@ to make sure Clang also works on non-GuixSD systems.
// The selection of paths to try here is designed to match the patterns
which
// the GCC driver itself uses, as this is part of the GCC-compatible driver.
-@@ -3043,14 +3047,12 @@ Linux::Linux(const Driver &D, const llvm
- addPathIfExists(D.Dir + "/../" + OSLibDir, Paths);
- }
+@@ -3194,6 +3198,10 @@
-- addPathIfExists(SysRoot + "/lib/" + MultiarchTriple, Paths);
-- addPathIfExists(SysRoot + "/lib/../" + OSLibDir, Paths);
-- addPathIfExists(SysRoot + "/usr/lib/" + MultiarchTriple, Paths);
-- addPathIfExists(SysRoot + "/usr/lib/../" + OSLibDir, Paths);
--
- // Try walking via the GCC triple path in case of biarch or multiarch GCC
- // installations with strange symlinks.
- if (GCCInstallation.isValid()) {
-+ // The following code would end up adding things like
-+ // "/usr/lib/x86_64-unknown-linux-gnu/../../lib64" to the search path.
-+#if 0
- addPathIfExists(SysRoot + "/usr/lib/" + GCCInstallation.getTriple().str()
+
- "/../../" + OSLibDir, Paths);
-
-@@ -3060,6 +3062,7 @@ Linux::Linux(const Driver &D, const llvm
- addPathIfExists(GCCInstallation.getInstallPath() +
- BiarchSibling.gccSuffix(), Paths);
- }
-+#endif
-
- // See comments above on the multilib variant for details of why this is
- // included even from outside the sysroot.
-@@ -3083,8 +3086,9 @@ Linux::Linux(const Driver &D, const llvm
- if (StringRef(D.Dir).startswith(SysRoot))
- addPathIfExists(D.Dir + "/../lib", Paths);
-
-- addPathIfExists(SysRoot + "/lib", Paths);
-- addPathIfExists(SysRoot + "/usr/lib", Paths);
+ addPathIfExists(SysRoot + "/lib", Paths);
+ addPathIfExists(SysRoot + "/usr/lib", Paths);
++
+ // Add libc's lib/ directory to the search path, so that crt1.o, crti.o,
+ // and friends can be found.
+ addPathIfExists("@GLIBC_LIBDIR@", Paths);
}
bool Linux::HasNativeLLVMSupport() const {
+@@ -3384,6 +3392,34 @@
+ addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/include");
+
+ addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/include");
++
++ // Check for configure-time "extra" C include directories. When
constructing a
++ // toolchain, @C_EXTRA_INCLUDE_DIRS@ should be replaced with something like
a
++ // colon-separated string of the include dirs of libc and kernel headers.
++ //
++ // The reason why we use this mechanism instead of C_INCLUDE_DIRS above is
++ // because when a user supplies clang with --sysroot, the normal expectation
++ // is that clang will detect and add the proper $SYSROOT/$MULTIARCHINCL,
++ // $SYSROOT/include, and $SYSROOT/usr/include to its list of search paths.
++ // However, if C_INCLUDE_DIRS is not empty, this function will return early
++ // and not attempt to add the aforementioned search paths, which is not
++ // desirable.
++ //
++ // By adding our configure-time "extra" C include directories here, after
++ // we've added $SYSROOT/include and $SYSROOT/usr/include, we make sure that
IF
++ // --sysroot is supplied on the command line, we pick up the expected search
++ // paths in the $SYSROOT, and that they come before our configure-time
"extra"
++ // C include directories.
++ StringRef CExtraIncludeDirs("@C_EXTRA_INCLUDE_DIRS@");
++ if (CExtraIncludeDirs != "") {
++ SmallVector<StringRef, 5> dirs;
++ CExtraIncludeDirs.split(dirs, ":");
++ for (StringRef dir : dirs) {
++ StringRef Prefix =
++ llvm::sys::path::is_absolute(dir) ? StringRef(SysRoot) : "";
++ addExternCSystemInclude(DriverArgs, CC1Args, Prefix + dir);
++ }
++ }
+ }
+
+ /// \brief Helper to add the variant paths of a libstdc++ installation.
diff --git a/gnu/packages/patches/clang-3.8-libc-search-path.patch
b/gnu/packages/patches/clang-3.8-libc-search-path.patch
index 0f7d0a4add..243d167755 100644
--- a/gnu/packages/patches/clang-3.8-libc-search-path.patch
+++ b/gnu/packages/patches/clang-3.8-libc-search-path.patch
@@ -29,41 +29,49 @@ changes in clang 3.8.
// The selection of paths to try here is designed to match the patterns
which
// the GCC driver itself uses, as this is part of the GCC-compatible driver.
-@@ -3771,14 +3775,12 @@
- addPathIfExists(D, D.Dir + "/../" + OSLibDir, Paths);
- }
+@@ -3817,6 +3821,10 @@
-- addPathIfExists(D, SysRoot + "/lib/" + MultiarchTriple, Paths);
-- addPathIfExists(D, SysRoot + "/lib/../" + OSLibDir, Paths);
-- addPathIfExists(D, SysRoot + "/usr/lib/" + MultiarchTriple, Paths);
-- addPathIfExists(D, SysRoot + "/usr/lib/../" + OSLibDir, Paths);
--
- // Try walking via the GCC triple path in case of biarch or multiarch GCC
- // installations with strange symlinks.
- if (GCCInstallation.isValid()) {
-+ // The following code would end up adding things like
-+ // "/usr/lib/x86_64-unknown-linux-gnu/../../lib64" to the search path.
-+#if 0
- addPathIfExists(D,
- SysRoot + "/usr/lib/" + GCCInstallation.getTriple().str()
+
- "/../../" + OSLibDir,
-@@ -3791,6 +3793,7 @@
- BiarchSibling.gccSuffix(),
- Paths);
- }
-+#endif
-
- // See comments above on the multilib variant for details of why this is
- // included even from outside the sysroot.
-@@ -3815,8 +3818,9 @@
- if (StringRef(D.Dir).startswith(SysRoot))
- addPathIfExists(D, D.Dir + "/../lib", Paths);
-
-- addPathIfExists(D, SysRoot + "/lib", Paths);
-- addPathIfExists(D, SysRoot + "/usr/lib", Paths);
+ addPathIfExists(D, SysRoot + "/lib", Paths);
+ addPathIfExists(D, SysRoot + "/usr/lib", Paths);
++
+ // Add libc's lib/ directory to the search path, so that crt1.o, crti.o,
+ // and friends can be found.
+ addPathIfExists(D, "@GLIBC_LIBDIR@", Paths);
}
bool Linux::HasNativeLLVMSupport() const { return true; }
+@@ -4026,6 +4034,34 @@
+ addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/include");
+
+ addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/include");
++
++ // Check for configure-time "extra" C include directories. When
constructing a
++ // toolchain, @C_EXTRA_INCLUDE_DIRS@ should be replaced with something like
a
++ // colon-separated string of the include dirs of libc and kernel headers.
++ //
++ // The reason why we use this mechanism instead of C_INCLUDE_DIRS above is
++ // because when a user supplies clang with --sysroot, the normal expectation
++ // is that clang will detect and add the proper $SYSROOT/$MULTIARCHINCL,
++ // $SYSROOT/include, and $SYSROOT/usr/include to its list of search paths.
++ // However, if C_INCLUDE_DIRS is not empty, this function will return early
++ // and not attempt to add the aforementioned search paths, which is not
++ // desirable.
++ //
++ // By adding our configure-time "extra" C include directories here, after
++ // we've added $SYSROOT/include and $SYSROOT/usr/include, we make sure that
IF
++ // --sysroot is supplied on the command line, we pick up the expected search
++ // paths in the $SYSROOT, and that they come before our configure-time
"extra"
++ // C include directories.
++ StringRef CExtraIncludeDirs("@C_EXTRA_INCLUDE_DIRS@");
++ if (CExtraIncludeDirs != "") {
++ SmallVector<StringRef, 5> dirs;
++ CExtraIncludeDirs.split(dirs, ":");
++ for (StringRef dir : dirs) {
++ StringRef Prefix =
++ llvm::sys::path::is_absolute(dir) ? StringRef(SysRoot) : "";
++ addExternCSystemInclude(DriverArgs, CC1Args, Prefix + dir);
++ }
++ }
+ }
+
+
diff --git a/gnu/packages/patches/clang-6.0-libc-search-path.patch
b/gnu/packages/patches/clang-6.0-libc-search-path.patch
index a62e8063c2..d80c798467 100644
--- a/gnu/packages/patches/clang-6.0-libc-search-path.patch
+++ b/gnu/packages/patches/clang-6.0-libc-search-path.patch
@@ -8,18 +8,17 @@ to make sure Clang also works on non-GuixSD systems.
--- cfe-6.0.0.src/lib/Driver/ToolChains/Linux.cpp
+++ cfe-6.0.0.src/lib/Driver/ToolChains/Linux.cpp
-@@ -207,7 +207,9 @@
- PPaths.push_back(Twine(GCCInstallation.getParentLibPath() + "/../" +
+@@ -208,6 +208,9 @@
GCCInstallation.getTriple().str() + "/bin")
.str());
--
+
+ // Comment out the distro-specific tweaks so that they don't bite when
+ // using Guix on a foreign distro.
+#if 0
Distro Distro(D.getVFS());
if (Distro.IsAlpineLinux()) {
-@@ -255,6 +257,7 @@
+@@ -255,6 +258,7 @@
if (IsAndroid || Distro.IsOpenSUSE())
ExtraOpts.push_back("--enable-new-dtags");
@@ -27,41 +26,49 @@ to make sure Clang also works on non-GuixSD systems.
// The selection of paths to try here is designed to match the patterns
which
// the GCC driver itself uses, as this is part of the GCC-compatible driver.
-@@ -329,14 +332,12 @@
- addPathIfExists(D, D.Dir + "/../" + OSLibDir, Paths);
- }
-
-- addPathIfExists(D, SysRoot + "/lib/" + MultiarchTriple, Paths);
-- addPathIfExists(D, SysRoot + "/lib/../" + OSLibDir, Paths);
-- addPathIfExists(D, SysRoot + "/usr/lib/" + MultiarchTriple, Paths);
-- addPathIfExists(D, SysRoot + "/usr/lib/../" + OSLibDir, Paths);
--
- // Try walking via the GCC triple path in case of biarch or multiarch GCC
- // installations with strange symlinks.
- if (GCCInstallation.isValid()) {
-+ // The following code would end up adding things like
-+ // "/usr/lib/x86_64-unknown-linux-gnu/../../lib64" to the search path.
-+#if 0
- addPathIfExists(D,
- SysRoot + "/usr/lib/" + GCCInstallation.getTriple().str()
+
- "/../../" + OSLibDir,
-@@ -349,6 +350,7 @@
- BiarchSibling.gccSuffix(),
- Paths);
- }
-+#endif
+@@ -375,6 +379,10 @@
- // See comments above on the multilib variant for details of why this is
- // included even from outside the sysroot.
-@@ -373,8 +375,9 @@
- if (StringRef(D.Dir).startswith(SysRoot))
- addPathIfExists(D, D.Dir + "/../lib", Paths);
-
-- addPathIfExists(D, SysRoot + "/lib", Paths);
-- addPathIfExists(D, SysRoot + "/usr/lib", Paths);
+ addPathIfExists(D, SysRoot + "/lib", Paths);
+ addPathIfExists(D, SysRoot + "/usr/lib", Paths);
++
+ // Add libc's lib/ directory to the search path, so that crt1.o, crti.o,
+ // and friends can be found.
+ addPathIfExists(D, "@GLIBC_LIBDIR@", Paths);
}
bool Linux::HasNativeLLVMSupport() const { return true; }
+@@ -710,6 +718,34 @@
+ addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/include");
+
+ addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/include");
++
++ // Check for configure-time "extra" C include directories. When
constructing a
++ // toolchain, @C_EXTRA_INCLUDE_DIRS@ should be replaced with something like
a
++ // colon-separated string of the include dirs of libc and kernel headers.
++ //
++ // The reason why we use this mechanism instead of C_INCLUDE_DIRS above is
++ // because when a user supplies clang with --sysroot, the normal expectation
++ // is that clang will detect and add the proper $SYSROOT/$MULTIARCHINCL,
++ // $SYSROOT/include, and $SYSROOT/usr/include to its list of search paths.
++ // However, if C_INCLUDE_DIRS is not empty, this function will return early
++ // and not attempt to add the aforementioned search paths, which is not
++ // desirable.
++ //
++ // By adding our configure-time "extra" C include directories here, after
++ // we've added $SYSROOT/include and $SYSROOT/usr/include, we make sure that
IF
++ // --sysroot is supplied on the command line, we pick up the expected search
++ // paths in the $SYSROOT, and that they come before our configure-time
"extra"
++ // C include directories.
++ StringRef CExtraIncludeDirs("@C_EXTRA_INCLUDE_DIRS@");
++ if (CExtraIncludeDirs != "") {
++ SmallVector<StringRef, 5> dirs;
++ CExtraIncludeDirs.split(dirs, ":");
++ for (StringRef dir : dirs) {
++ StringRef Prefix =
++ llvm::sys::path::is_absolute(dir) ? StringRef(SysRoot) : "";
++ addExternCSystemInclude(DriverArgs, CC1Args, Prefix + dir);
++ }
++ }
+ }
+
+ static std::string DetectLibcxxIncludePath(StringRef base) {
diff --git a/gnu/packages/patches/clang-7.0-libc-search-path.patch
b/gnu/packages/patches/clang-7.0-libc-search-path.patch
index 07ff8c90bd..445b5d17ac 100644
--- a/gnu/packages/patches/clang-7.0-libc-search-path.patch
+++ b/gnu/packages/patches/clang-7.0-libc-search-path.patch
@@ -8,7 +8,7 @@ to make sure Clang also works on non-GuixSD systems.
--- a/lib/Driver/ToolChains/Linux.cpp
+++ b/lib/Driver/ToolChains/Linux.cpp
-@@ -225,7 +225,9 @@ Linux::Linux(const Driver &D, const llvm::Triple &Triple,
const ArgList &Args)
+@@ -225,7 +225,9 @@
PPaths.push_back(Twine(GCCInstallation.getParentLibPath() + "/../" +
GCCInstallation.getTriple().str() + "/bin")
.str());
@@ -19,7 +19,7 @@ to make sure Clang also works on non-GuixSD systems.
Distro Distro(D.getVFS());
if (Distro.IsAlpineLinux()) {
-@@ -284,6 +286,7 @@ Linux::Linux(const Driver &D, const llvm::Triple &Triple,
const ArgList &Args)
+@@ -284,6 +286,7 @@
if (IsAndroid || Distro.IsOpenSUSE())
ExtraOpts.push_back("--enable-new-dtags");
@@ -27,56 +27,49 @@ to make sure Clang also works on non-GuixSD systems.
// The selection of paths to try here is designed to match the patterns
which
// the GCC driver itself uses, as this is part of the GCC-compatible driver.
-@@ -342,7 +345,7 @@ Linux::Linux(const Driver &D, const llvm::Triple &Triple,
const ArgList &Args)
- // the cross. Note that GCC does include some of these directories in some
- // configurations but this seems somewhere between questionable and simply
- // a bug.
-- if (StringRef(LibPath).startswith(SysRoot)) {
-+ if (0) {
- addPathIfExists(D, LibPath + "/" + MultiarchTriple, Paths);
- addPathIfExists(D, LibPath + "/../" + OSLibDir, Paths);
- }
-@@ -361,6 +364,8 @@ Linux::Linux(const Driver &D, const llvm::Triple &Triple,
const ArgList &Args)
- addPathIfExists(D, SysRoot + "/lib/" + MultiarchTriple, Paths);
- addPathIfExists(D, SysRoot + "/lib/../" + OSLibDir, Paths);
+@@ -431,6 +434,10 @@
-+ // This requires the commented distro tweaks above.
-+#if 0
- if (IsAndroid) {
- // Android sysroots contain a library directory for each supported OS
- // version as well as some unversioned libraries in the usual multiarch
-@@ -389,10 +394,14 @@ Linux::Linux(const Driver &D, const llvm::Triple
&Triple, const ArgList &Args)
- addPathIfExists(D, SysRoot + "/" + OSLibDir + "/" + ABIName, Paths);
- addPathIfExists(D, SysRoot + "/usr/" + OSLibDir + "/" + ABIName, Paths);
- }
-+#endif
-
- // Try walking via the GCC triple path in case of biarch or multiarch GCC
- // installations with strange symlinks.
- if (GCCInstallation.isValid()) {
-+ // The following code would end up adding things like
-+ // "/usr/lib/x86_64-unknown-linux-gnu/../../lib64" to the search path.
-+#if 0
- addPathIfExists(D,
- SysRoot + "/usr/lib/" + GCCInstallation.getTriple().str()
+
- "/../../" + OSLibDir,
-@@ -405,6 +414,7 @@ Linux::Linux(const Driver &D, const llvm::Triple &Triple,
const ArgList &Args)
- BiarchSibling.gccSuffix(),
- Paths);
- }
-+#endif
-
- // See comments above on the multilib variant for details of why this is
- // included even from outside the sysroot.
-@@ -429,8 +439,9 @@ Linux::Linux(const Driver &D, const llvm::Triple &Triple,
const ArgList &Args)
- if (StringRef(D.Dir).startswith(SysRoot))
- addPathIfExists(D, D.Dir + "/../lib", Paths);
-
-- addPathIfExists(D, SysRoot + "/lib", Paths);
-- addPathIfExists(D, SysRoot + "/usr/lib", Paths);
+ addPathIfExists(D, SysRoot + "/lib", Paths);
+ addPathIfExists(D, SysRoot + "/usr/lib", Paths);
++
+ // Add libc's lib/ directory to the search path, so that crt1.o, crti.o,
+ // and friends can be found.
+ addPathIfExists(D, "@GLIBC_LIBDIR@", Paths);
}
bool Linux::HasNativeLLVMSupport() const { return true; }
+@@ -794,6 +801,34 @@
+ addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/include");
+
+ addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/include");
++
++ // Check for configure-time "extra" C include directories. When
constructing a
++ // toolchain, @C_EXTRA_INCLUDE_DIRS@ should be replaced with something like
a
++ // colon-separated string of the include dirs of libc and kernel headers.
++ //
++ // The reason why we use this mechanism instead of C_INCLUDE_DIRS above is
++ // because when a user supplies clang with --sysroot, the normal expectation
++ // is that clang will detect and add the proper $SYSROOT/$MULTIARCHINCL,
++ // $SYSROOT/include, and $SYSROOT/usr/include to its list of search paths.
++ // However, if C_INCLUDE_DIRS is not empty, this function will return early
++ // and not attempt to add the aforementioned search paths, which is not
++ // desirable.
++ //
++ // By adding our configure-time "extra" C include directories here, after
++ // we've added $SYSROOT/include and $SYSROOT/usr/include, we make sure that
IF
++ // --sysroot is supplied on the command line, we pick up the expected search
++ // paths in the $SYSROOT, and that they come before our configure-time
"extra"
++ // C include directories.
++ StringRef CExtraIncludeDirs("@C_EXTRA_INCLUDE_DIRS@");
++ if (CExtraIncludeDirs != "") {
++ SmallVector<StringRef, 5> dirs;
++ CExtraIncludeDirs.split(dirs, ":");
++ for (StringRef dir : dirs) {
++ StringRef Prefix =
++ llvm::sys::path::is_absolute(dir) ? StringRef(SysRoot) : "";
++ addExternCSystemInclude(DriverArgs, CC1Args, Prefix + dir);
++ }
++ }
+ }
+
+ static std::string DetectLibcxxIncludePath(StringRef base) {