[Driver] Fuchsia defaults to -fno-math-errno

Patch by Roland McGrath

Differential Revision: https://reviews.llvm.org/D35747

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@308855 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Driver/ToolChains/Fuchsia.h

@@ -42,6 +42,7 @@ public:
 
   bool HasNativeLLVMSupport() const override { return true; }
   bool IsIntegratedAssemblerDefault() const override { return true; }
+  bool IsMathErrnoDefault() const override { return false; }
   RuntimeLibType GetDefaultRuntimeLibType() const override {
     return ToolChain::RLT_CompilerRT;
   }

test/Driver/fast-math.c

@@ -93,6 +93,8 @@
 // RUN:   | FileCheck --check-prefix=CHECK-NO-MATH-ERRNO %s
 // RUN: %clang -### -target x86_64-unknown-dragonfly -c %s 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-NO-MATH-ERRNO %s
+// RUN: %clang -### -target x86_64-fuchsia -c %s 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-NO-MATH-ERRNO %s
 //
 // Check that -ffast-math disables -fmath-errno, and -fno-fast-math merely
 // preserves the target default. Also check various flag set operations between