Revert of [GN]: BUILD file housecleaning

build/toolchain/mac/BUILD.gn

Index: build/toolchain/mac/BUILD.gn
diff --git a/build/toolchain/mac/BUILD.gn b/build/toolchain/mac/BUILD.gn
index b0c233a19a43f6ee20e7abb9007a845825674fdc..dd3ff6107103260703700e4915db9bffa9f371ca 100644
--- a/build/toolchain/mac/BUILD.gn
+++ b/build/toolchain/mac/BUILD.gn
@@ -50,7 +50,10 @@ template("mac_toolchain") {
 
     tool("cc") {
       depfile = "{{output}}.d"
-      precompiled_header_type = "gcc"
+
+      # TODO(andybons): enable this when GCC PCH support in the binary has been
+      # rolled.
+      #precompiled_header_type = "gcc"
       command = "$cc -MMD -MF $depfile {{defines}} {{include_dirs}} {{cflags}} {{cflags_c}} -c {{source}} -o {{output}}"
       depsformat = "gcc"
       description = "CC {{output}}"
@@ -61,7 +64,10 @@ template("mac_toolchain") {
 
     tool("cxx") {
       depfile = "{{output}}.d"
-      precompiled_header_type = "gcc"
+
+      # TODO(andybons): enable this when GCC PCH support in the binary has been
+      # rolled.
+      #precompiled_header_type = "gcc"
       command = "$cxx -MMD -MF $depfile {{defines}} {{include_dirs}} {{cflags}} {{cflags_cc}} -c {{source}} -o {{output}}"
       depsformat = "gcc"
       description = "CXX {{output}}"
@@ -73,7 +79,7 @@ template("mac_toolchain") {
     tool("asm") {
       # For GCC we can just use the C compiler to compile assembly.
       depfile = "{{output}}.d"
-      command = "$cc -MMD -MF $depfile {{defines}} {{include_dirs}} {{asmflags}} -c {{source}} -o {{output}}"
+      command = "$cc -MMD -MF $depfile {{defines}} {{include_dirs}} {{cflags}} {{cflags_c}} -c {{source}} -o {{output}}"
       depsformat = "gcc"
       description = "ASM {{output}}"
       outputs = [
@@ -84,7 +90,10 @@ template("mac_toolchain") {
     tool("objc") {
       depfile = "{{output}}.d"
       command = "$cxx -MMD -MF $depfile {{defines}} {{include_dirs}} {{cflags}} {{cflags_objc}} -c {{source}} -o {{output}}"
-      precompiled_header_type = "gcc"
+
+      # TODO(andybons): enable this when GCC PCH support in the binary has been
+      # rolled.
+      #precompiled_header_type = "gcc"
       command = "$cxx -MMD -MF $depfile {{defines}} {{include_dirs}} {{cflags}} {{cflags_c}} {{cflags_objc}} -c {{source}} -o {{output}}"
       depsformat = "gcc"
       description = "OBJC {{output}}"
@@ -96,7 +105,10 @@ template("mac_toolchain") {
     tool("objcxx") {
       depfile = "{{output}}.d"
       command = "$cxx -MMD -MF $depfile {{defines}} {{include_dirs}} {{cflags}} {{cflags_objcc}} -c {{source}} -o {{output}}"
-      precompiled_header_type = "gcc"
+
+      # TODO(andybons): enable this when GCC PCH support in the binary has been
+      # rolled.
+      #precompiled_header_type = "gcc"
       depsformat = "gcc"
       description = "OBJCXX {{output}}"
       outputs = [