[Autotools] Unicode's CFLAGS enforce -D_FORTIFY_SOURCE=2, -D_REENTRAN…

…T=1, causing faulty Clang builds

https://bugs.webkit.org/show_bug.cgi?id=119685

Reviewed by Gustavo Noronha Silva.

icu-config includes '-D_FORTIFY_SOURCE=2 -D_REENTRANT=1' when printing out C preprocessor flags that are used
as the C compiler flags to avoid other unwanted compiler options. This causes problems when building optimized
builds with Clang because of a bug in that compiler:
http://llvm.org/bugs/show_bug.cgi?id=16821

To avoid that, the C preprocessor search flags, as printed by `icu-config --cppflags-searchpath` are now used
the Unicode dependency's C compiler flags, avoiding unconditionally specifying the two macros.

To adjust for that, the `-pthread` flag is added to the global CFLAGS and CXXFLAGS variables, ensuring
the _REENTRANT define is set to 1 and declaring the flag globally instead of relying on Glib dependency's
C compiler flags to do so for us. -D_FORTIFY_SOURCE=2 is only added to the CFLAGS and CXXFLAGS variables if
the compiler in use is gcc or g++, preventing the Clang builds to malfunction.

* Source/autotools/FindDependencies.m4:
* Source/autotools/SetupCompilerFlags.m4:


Canonical link: https://commits.webkit.org/137697@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@154008 268f45cc-cd09-0410-ab3c-d52691b4dbfc

ChangeLog

@@ -1,3 +1,26 @@
+2013-08-13  Zan Dobersek  <zdobersek@igalia.com>
+
+        [Autotools] Unicode's CFLAGS enforce -D_FORTIFY_SOURCE=2, -D_REENTRANT=1, causing faulty Clang builds
+        https://bugs.webkit.org/show_bug.cgi?id=119685
+
+        Reviewed by Gustavo Noronha Silva.
+
+        icu-config includes '-D_FORTIFY_SOURCE=2 -D_REENTRANT=1' when printing out C preprocessor flags that are used
+        as the C compiler flags to avoid other unwanted compiler options. This causes problems when building optimized
+        builds with Clang because of a bug in that compiler:
+        http://llvm.org/bugs/show_bug.cgi?id=16821
+
+        To avoid that, the C preprocessor search flags, as printed by `icu-config --cppflags-searchpath` are now used
+        the Unicode dependency's C compiler flags, avoiding unconditionally specifying the two macros.
+
+        To adjust for that, the `-pthread` flag is added to the global CFLAGS and CXXFLAGS variables, ensuring
+        the _REENTRANT define is set to 1 and declaring the flag globally instead of relying on Glib dependency's
+        C compiler flags to do so for us. -D_FORTIFY_SOURCE=2 is only added to the CFLAGS and CXXFLAGS variables if
+        the compiler in use is gcc or g++, preventing the Clang builds to malfunction.
+
+        * Source/autotools/FindDependencies.m4:
+        * Source/autotools/SetupCompilerFlags.m4:
+
 2013-08-13  Zan Dobersek  <zdobersek@igalia.com>
 
         [Autotools] Don't compare $CC, $CXX to exact compiler names

Source/autotools/FindDependencies.m4

@@ -125,7 +125,7 @@ case "$host" in
 
         # We don't use --cflags as this gives us a lot of things that we don't necessarily want,
         # like debugging and optimization flags. See man (1) icu-config for more info.
-        UNICODE_CFLAGS=`$icu_config --cppflags`
+        UNICODE_CFLAGS=`$icu_config --cppflags-searchpath`
         UNICODE_LIBS=`$icu_config --ldflags-libsonly`
         ;;
 esac

Source/autotools/SetupCompilerFlags.m4

@@ -1,7 +1,7 @@
 # Use C99 as the language standard for C code.
-CFLAGS="$CFLAGS -std=c99"
+CFLAGS="$CFLAGS -pthread -std=c99"
 # Use the C++11 standard. Do not warn about C++11 incompatibilities.
-CXXFLAGS="$CXXFLAGS -std=c++11 -Wno-c++11-compat"
+CXXFLAGS="$CXXFLAGS -pthread -std=c++11 -Wno-c++11-compat"
 
 # Clang requires suppression of unused arguments warnings.
 if test "$c_compiler" = "clang"; then
@@ -15,6 +15,13 @@ if test "$cxx_compiler" = "clang++"; then
     CXXFLAGS="$CXXFLAGS -stdlib=libstdc++ -Wno-c++11-extensions -Qunused-arguments"
 fi
 
+if test "$c_compiler" = "gcc"; then
+    CFLAGS="$CFLAGS -D_FORTIFY_SOURCE=2"
+fi
+if test "$cxx_compiler" = "g++"; then
+    CXXFLAGS="$CXXFLAGS -D_FORTIFY_SOURCE=2"
+fi
+
 if test "$host_cpu" = "sh4"; then
     CXXFLAGS="$CXXFLAGS -mieee -w"
     CFLAGS="$CFLAGS -mieee -w"