Fixed or silenced all warnings and turned on warnings-as-errors.

- Silence -Wheader-hygiene warning on Clang. Between fx_agg_driver.cpp
and fxjs_v8.h there are hundreds or thousands of things that depend on
"using namespace", so it is best to just suppress this warning than
fix it.
- gzguts.h: Include unistd.h on all non-Windows platforms, not just
Apple platforms. Fixes implicit include warnings on Linux.
- Added parens to silence a warning about mixing && and ||.
- Removed a check if an enum is negative. Enums can be unsigned,
generating an always-false warning. The check isn't necessary.
- Removed some statements that are just names of variables that do
nothing.

BUG=375114

Patch by Matt Giuca <mgiuca@chromium.org>

2 files changed, 3 insertions, 5 deletions

diff --git a/core/src/fxcodec/fx_zlib/zlib_v128/gzguts.h b/core/src/fxcodec/fx_zlib/zlib_v128/gzguts.h
index e4454aa65d..a877c0eee3 100644
--- a/core/src/fxcodec/fx_zlib/zlib_v128/gzguts.h
+++ b/core/src/fxcodec/fx_zlib/zlib_v128/gzguts.h
@@ -29,10 +29,8 @@
 
 #ifdef _WIN32
 #  include <stddef.h>
-#endif
-
-#ifdef __APPLE__
-#include <unistd.h>
+#else
+#  include <unistd.h>
 #endif
 
 #if defined(__TURBOC__) || defined(_MSC_VER) || defined(_WIN32)
diff --git a/core/src/fxcodec/lcms2/lcms2-2.6/src/cmsplugin.c b/core/src/fxcodec/lcms2/lcms2-2.6/src/cmsplugin.c
index 55928b7018..8903d2bd61 100644
--- a/core/src/fxcodec/lcms2/lcms2-2.6/src/cmsplugin.c
+++ b/core/src/fxcodec/lcms2/lcms2-2.6/src/cmsplugin.c
@@ -689,7 +689,7 @@ void* _cmsContextGetClientChunk(cmsContext ContextID, _cmsMemoryClient mc)
     struct _cmsContext_struct* ctx;
     void *ptr;
 
-    if (mc < 0 || mc >= MemoryClientMax) {
+    if (mc >= MemoryClientMax) {
         cmsSignalError(ContextID, cmsERROR_RANGE, "Bad context client");
         return NULL;
     }