compilers: Don't run built-in checks on MSVC

MSVC does not have built-ins, so this is totally useless. Instead, add
a test for intrinsics to ensure that we do find them.

mesonbuild/compilers.py

@@ -1046,6 +1046,10 @@ class CCompiler(Compiler):
         if self.links(templ.format(**fargs), env, extra_args, dependencies):
             return True
 
+        # MSVC does not have compiler __builtin_-s.
+        if self.get_id() == 'msvc':
+            return False
+
         # Detect function as a built-in
         #
         # Some functions like alloca() are defined as compiler built-ins which

test cases/common/43 has function/meson.build

@@ -28,6 +28,11 @@ foreach cc : compilers
     assert(cc.has_function('fprintf', prefix : '#include <stdio.h>',
                            args : unit_test_args),
            '"fprintf" function not found with include (on msvc).')
+    # Compiler intrinsics
+    assert(cc.has_function('strcmp'),
+           'strcmp intrinsic should have been found on MSVC')
+    assert(cc.has_function('strcmp', prefix : '#include <string.h>'),
+           'strcmp intrinsic should have been found with #include on MSVC')
   endif
 
   if cc.has_function('hfkerhisadf', prefix : '#include<stdio.h>',