Remove GCC checks

Clang is always used now, so we can remove all the GCC checks. Removing
GCC-specific configuration will happen in the next CL.

Test: m
Change-Id: I4835ecf6062159315d0dfb07b098e60bff033a8a
diff --git a/cc/sanitize.go b/cc/sanitize.go
index b2fc63f..5dcaf76 100644
--- a/cc/sanitize.go
+++ b/cc/sanitize.go
@@ -164,17 +164,15 @@
 	var globalSanitizers []string
 	var globalSanitizersDiag []string
 
-	if ctx.clang() {
-		if ctx.Host() {
-			if !ctx.Windows() {
-				globalSanitizers = ctx.Config().SanitizeHost()
-			}
-		} else {
-			arches := ctx.Config().SanitizeDeviceArch()
-			if len(arches) == 0 || inList(ctx.Arch().ArchType.Name, arches) {
-				globalSanitizers = ctx.Config().SanitizeDevice()
-				globalSanitizersDiag = ctx.Config().SanitizeDeviceDiag()
-			}
+	if ctx.Host() {
+		if !ctx.Windows() {
+			globalSanitizers = ctx.Config().SanitizeHost()
+		}
+	} else {
+		arches := ctx.Config().SanitizeDeviceArch()
+		if len(arches) == 0 || inList(ctx.Arch().ArchType.Name, arches) {
+			globalSanitizers = ctx.Config().SanitizeDevice()
+			globalSanitizersDiag = ctx.Config().SanitizeDeviceDiag()
 		}
 	}
 
@@ -369,10 +367,6 @@
 		return flags
 	}
 
-	if !ctx.clang() {
-		ctx.ModuleErrorf("Use of sanitizers requires clang")
-	}
-
 	var sanitizers []string
 	var diagSanitizers []string