toolchain-funcs.eclass: Add helpful tc-is-{gcc,clang} wrappers

eclass/tests/toolchain-funcs.sh

@@ -120,13 +120,41 @@ export CC=gcc
 )
 tend $?
 
+tbegin "tc-is-gcc (gcc)"
+(
+export CC=gcc
+tc-is-gcc
+)
+tend $?
+
+tbegin "! tc-is-clang (gcc)"
+(
+export CC=gcc
+! tc-is-clang
+)
+tend $?
+
 if type -P clang &>/dev/null; then
 	tbegin "tc-get-compiler-type (clang)"
 	(
 	export CC=clang
 	[[ $(tc-get-compiler-type) == clang ]]
 	)
 	tend $?
+
+	tbegin "! tc-is-gcc (clang)"
+	(
+	export CC=clang
+	! tc-is-gcc
+	)
+	tend $?
+
+	tbegin "tc-is-clang (clang)"
+	(
+	export CC=clang
+	tc-is-clang
+	)
+	tend $?
 fi
 
 if type -P pathcc &>/dev/null; then

eclass/toolchain-funcs.eclass

@@ -607,6 +607,18 @@ tc-get-compiler-type() {
 	esac
 }
 
+# @FUNCTION: tc-is-gcc
+# @RETURN: Shell true if the current compiler is GCC, false otherwise.
+tc-is-gcc() {
+	[[ $(tc-get-compiler-type) == gcc ]]
+}
+
+# @FUNCTION: tc-is-clang
+# @RETURN: Shell true if the current compiler is clang, false otherwise.
+tc-is-clang() {
+	[[ $(tc-get-compiler-type) == clang ]]
+}
+
 # Internal func.  The first argument is the version info to expand.
 # Query the preprocessor to improve compatibility across different
 # compilers rather than maintaining a --version flag matrix. #335943