Introduce guard for aarch64 GCC compilation. (#4647)

* Introduce fix for aarch64 GCC compilation.

* Use a cmake-based check_include_file.

* Move comment.

BUILD.bazel

@@ -26,10 +26,13 @@ genrule(
     name = "sed_config_h",
     srcs = ["cmake/config.h.cmake"],
     outs = ["config.h"],
+    # TODO: We should actually check these properly instead of just #undefing them.
+    # Maybe select() can help here?
     cmd = " | ".join([
         "sed 's|cmakedefine|define|g' < $(SRCS)",
         "sed 's|define HAVE_LIBGC 1|undef HAVE_LIBGC|g'",
         "sed 's|define HAVE_LIBBACKTRACE 1|undef HAVE_LIBBACKTRACE|g' > $(OUTS)",
+        "sed 's|define HAVE_MM_MALLOC_H 1|undef HAVE_MM_MALLOC_H|g' > $(OUTS)",
     ]),
     visibility = ["//visibility:private"],
 )

CMakeLists.txt

@@ -237,6 +237,7 @@ include (CheckIncludeFile)
 check_include_file (execinfo.h HAVE_EXECINFO_H)
 check_include_file (ucontext.h HAVE_UCONTEXT_H)
 check_include_file (backtrace-supported.h HAVE_LIBBACKTRACE)
+check_include_file(mm_malloc.h, HAVE_MM_MALLOC_H)
 include (CheckIncludeFileCXX)
 check_include_file_cxx (cxxabi.h HAVE_CXXABI_H)
 

cmake/config.h.cmake

@@ -33,3 +33,6 @@
 
 /* Define to 1 if you have the cxxabi.h header */
 #cmakedefine HAVE_CXXABI_H 1
+
+/* Define to 1 if you have the mm_malloc.h header */
+#cmakedefine HAVE_MM_MALLOC_H 1

lib/gc.cpp

@@ -19,7 +19,10 @@ limitations under the License.
 // of this to allow posix_memalign redeclaration with / without exception
 // specifier. As we define posix_memalign below in this file we really need to
 // ensure the proper include order to workaround this weirdness.
+// Some systems (e.g., GCC compiling on arm64) do not have mm_malloc.h. We need to skip it.
+#if HAVE_MM_MALLOC_H
 #include <mm_malloc.h>  // NOLINT(build/include_order)
+#endif
 
 #include "config.h"
 #if HAVE_LIBGC