Make the Mac build work.

tools/gn/secondary/build/config/mac/BUILD.gn

Index: tools/gn/secondary/build/config/mac/BUILD.gn
diff --git a/tools/gn/secondary/build/config/mac/BUILD.gn b/tools/gn/secondary/build/config/mac/BUILD.gn
index 7e13aed748182e598355ee792141719fad6753b1..a4026b6e36e8f68874cb1d33d50e7b8bda1c53ac 100644
--- a/tools/gn/secondary/build/config/mac/BUILD.gn
+++ b/tools/gn/secondary/build/config/mac/BUILD.gn
@@ -2,8 +2,17 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+# On Mac, this is usefor everything except static libraries.
+config("mac_dynamic_flags") {
+  ldflags = [
+    "-Wl,-search_paths_first",
+  ]
+}
+
+
 cc = "../../third_party/llvm-build/Release+Asserts/bin/clang"
 cxx = "../../third_party/llvm-build/Release+Asserts/bin/clang++"
+ld = cxx
 
 toolchain("clang") {
   tool("cc") {
@@ -19,13 +28,13 @@ toolchain("clang") {
     deps = "gcc"
   }
   tool("objc") {
-    command = "$cc -MMD -MF \$out.d \$defines \$includes \$cflags \$cflags_objc \$cflags_pch_objc -c \$in -o \$out"
+    command = "$cc -MMD -MF \$out.d \$defines \$includes \$cflags \$cflags_c \$cflags_objc \$cflags_pch_objc -c \$in -o \$out"
     description = "OBJC \$out"
     depfile = "\$out.d"
     deps = "gcc"
   }
   tool("objcxx") {
-    command = "$cxx -MMD -MF \$out.d \$defines \$includes \$cflags \$cflags_objcc \$cflags_pch_objcc -c \$in -o \$out"
+    command = "$cxx -MMD -MF \$out.d \$defines \$includes \$cflags \$cflags_cc \$cflags_objcc \$cflags_pch_objcc -c \$in -o \$out"
     description = "OBJCXX \$out"
     depfile = "\$out.d"
     deps = "gcc"
@@ -35,19 +44,19 @@ toolchain("clang") {
     description = "LIBTOOL-STATIC \$out, POSTBUILDS"
   }
   tool("solink") {
-    command = "if [ ! -e \$lib -o ! -e \${lib}.TOC ] || otool -l \$lib | grep -q LC_REEXPORT_DYLIB ; then \$ld -shared \$ldflags -o \$lib \$in \$solibs \$libs\$postbuilds && { otool -l \$lib | grep LC_ID_DYLIB -A 5; nm -gP \$lib | cut -f1-2 -d' ' | grep -v U\$\$; true; } > \${lib}.TOC; else \$ld -shared \$ldflags -o \$lib \$in \$solibs \$libs\$postbuilds && { otool -l \$lib | grep LC_ID_DYLIB -A 5; nm -gP \$lib | cut -f1-2 -d' ' | grep -v U\$\$; true; } > \${lib}.tmp && if ! cmp -s \${lib}.tmp \${lib}.TOC; then mv \${lib}.tmp \${lib}.TOC ; fi; fi"
+    command = "if [ ! -e \$lib -o ! -e \${lib}.TOC ] || otool -l \$lib | grep -q LC_REEXPORT_DYLIB ; then $ld -shared \$ldflags -o \$lib \$in \$solibs \$libs\$postbuilds && { otool -l \$lib | grep LC_ID_DYLIB -A 5; nm -gP \$lib | cut -f1-2 -d' ' | grep -v U\$\$; true; } > \${lib}.TOC; else $ld -shared \$ldflags -o \$lib \$in \$solibs \$libs\$postbuilds && { otool -l \$lib | grep LC_ID_DYLIB -A 5; nm -gP \$lib | cut -f1-2 -d' ' | grep -v U\$\$; true; } > \${lib}.tmp && if ! cmp -s \${lib}.tmp \${lib}.TOC; then mv \${lib}.tmp \${lib}.TOC ; fi; fi"
     description = "SOLINK \$lib, POSTBUILDS"
     #pool = "link_pool"
     restat = "1"
   }
   tool("solink_module") {
-    command = "if [ ! -e \$lib -o ! -e \${lib}.TOC ] || otool -l \$lib | grep -q LC_REEXPORT_DYLIB ; then \$ld -shared \$ldflags -o \$lib \$in \$solibs \$libs\$postbuilds && { otool -l \$lib | grep LC_ID_DYLIB -A 5; nm -gP \$lib | cut -f1-2 -d' ' | grep -v U\$\$; true; } > \${lib}.TOC; else \$ld -shared \$ldflags -o \$lib \$in \$solibs \$libs\$postbuilds && { otool -l \$lib | grep LC_ID_DYLIB -A 5; nm -gP \$lib | cut -f1-2 -d' ' | grep -v U\$\$; true; } > \${lib}.tmp && if ! cmp -s \${lib}.tmp \${lib}.TOC; then mv \${lib}.tmp \${lib}.TOC ; fi; fi"
+    command = "if [ ! -e \$lib -o ! -e \${lib}.TOC ] || otool -l \$lib | grep -q LC_REEXPORT_DYLIB ; then $ld -shared \$ldflags -o \$lib \$in \$solibs \$libs\$postbuilds && { otool -l \$lib | grep LC_ID_DYLIB -A 5; nm -gP \$lib | cut -f1-2 -d' ' | grep -v U\$\$; true; } > \${lib}.TOC; else $ld -shared \$ldflags -o \$lib \$in \$solibs \$libs\$postbuilds && { otool -l \$lib | grep LC_ID_DYLIB -A 5; nm -gP \$lib | cut -f1-2 -d' ' | grep -v U\$\$; true; } > \${lib}.tmp && if ! cmp -s \${lib}.tmp \${lib}.TOC; then mv \${lib}.tmp \${lib}.TOC ; fi; fi"
     description = "SOLINK(module) \$lib, POSTBUILDS"
     #pool = "link_pool"
     restat = "1"
   }
   tool("link") {
-    command = "\$ld \$ldflags -o \$out \$in \$solibs \$libs\$postbuilds"
+    command = "$ld \$ldflags -o \$out \$in \$solibs \$libs\$postbuilds"
     description = "LINK \$out, POSTBUILDS"
     #pool = "link_pool"
   }