GN: aix port along with linux_s390x, linux_ppc64 and linux_ppc64le support.

Most of the porting involves files inside /base.

This also fixes build/build_config.h not identifying PPC architectures correctly. Finally, it adds aix support to files inside tools/gn/, including the bootstrap script.

R=machenbach@chromium.org, dpranke@chromium.org, adamk@chromium.org
BUG=706728

Review-Url: https://codereview.chromium.org/2807463004
Cr-Original-Commit-Position: refs/heads/master@{#467484}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 0088ee5017f4bef6c27243a54d8998f993db11b8

build_config.h

@@ -59,6 +59,8 @@
 #define OS_SOLARIS 1
 #elif defined(__QNXNTO__)
 #define OS_QNX 1
+#elif defined(_AIX)
+#define OS_AIX 1
 #else
 #error Please add support for your platform in build/build_config.h
 #endif
@@ -75,10 +77,10 @@
 
 // For access to standard POSIXish features, use OS_POSIX instead of a
 // more specific macro.
-#if defined(OS_MACOSX) || defined(OS_LINUX) || defined(OS_FREEBSD) ||     \
-    defined(OS_NETBSD) || defined(OS_OPENBSD) || defined(OS_SOLARIS) ||   \
-    defined(OS_ANDROID) || defined(OS_OPENBSD) || defined(OS_SOLARIS) ||  \
-    defined(OS_ANDROID) || defined(OS_NACL) || defined(OS_QNX)
+#if defined(OS_AIX) || defined(OS_ANDROID) || defined(OS_FREEBSD) || \
+    defined(OS_LINUX) || defined(OS_MACOSX) || defined(OS_NACL) ||   \
+    defined(OS_NETBSD) || defined(OS_OPENBSD) || defined(OS_QNX) ||  \
+    defined(OS_SOLARIS)
 #define OS_POSIX 1
 #endif
 
@@ -121,21 +123,16 @@
 #define ARCH_CPU_S390 1
 #define ARCH_CPU_31_BITS 1
 #define ARCH_CPU_BIG_ENDIAN 1
-#elif defined(__PPC64__) && defined(__BIG_ENDIAN__)
+#elif (defined(__PPC64__) || defined(__PPC__)) && defined(__BIG_ENDIAN__)
 #define ARCH_CPU_PPC64_FAMILY 1
 #define ARCH_CPU_PPC64 1
 #define ARCH_CPU_64_BITS 1
 #define ARCH_CPU_BIG_ENDIAN 1
-#elif defined(__PPC64__) && defined(__LITTLE_ENDIAN__)
+#elif defined(__PPC64__)
 #define ARCH_CPU_PPC64_FAMILY 1
 #define ARCH_CPU_PPC64 1
 #define ARCH_CPU_64_BITS 1
 #define ARCH_CPU_LITTLE_ENDIAN 1
-#elif defined(__PPC__)
-#define ARCH_CPU_PPC_FAMILY 1
-#define ARCH_CPU_PPC 1
-#define ARCH_CPU_32_BITS 1
-#define ARCH_CPU_BIG_ENDIAN 1
 #elif defined(__ARMEL__)
 #define ARCH_CPU_ARM_FAMILY 1
 #define ARCH_CPU_ARMEL 1