ENH: only check flag on unix

Tests/Complex/Library/testConly.c

@@ -2,11 +2,13 @@
 
 int CsharedFunction()
 {
+#if !defined(_WIN32) || defined(__CYGWIN__)
 #ifndef TEST_C_FLAGS
   printf("TEST_C_FLAGS failed\n");
   return 0;
 #else
   printf("Passed: TEST_C_FLAGS passed\n");  
 #endif  
+#endif
   return 1;
 }

Tests/ComplexOneConfig/Library/testConly.c

@@ -2,11 +2,13 @@
 
 int CsharedFunction()
 {
+#if !defined(_WIN32) || defined(__CYGWIN__)
 #ifndef TEST_C_FLAGS
   printf("TEST_C_FLAGS failed\n");
   return 0;
 #else
   printf("Passed: TEST_C_FLAGS passed\n");  
 #endif  
+#endif
   return 1;
 }

Tests/ComplexRelativePaths/Library/testConly.c

@@ -2,11 +2,13 @@
 
 int CsharedFunction()
 {
+#if !defined(_WIN32) || defined(__CYGWIN__)
 #ifndef TEST_C_FLAGS
   printf("TEST_C_FLAGS failed\n");
   return 0;
 #else
   printf("Passed: TEST_C_FLAGS passed\n");  
 #endif  
+#endif
   return 1;
 }