Feature test C11 generics, since GCC lies about compliance

CMakeLists.txt

@@ -62,6 +62,14 @@ else()
 	set(BACKTRACE_L_FLAGS "")
 endif()
 
+check_c_source_compiles(
+    "#define print(x) _Generic((x), default : print_unknown)(x) \n void print_unknown(){} \n int main () { print(0); }"
+    HAS_GENERIC)
+
+if(HAS_GENERIC)
+    add_definitions(-DHAS_GENERIC)
+endif(HAS_GENERIC)
+
 if( ENABLE_RSVG )
 pkg_check_modules( RSVG librsvg-2.0>=2.14.0 )
 endif( ENABLE_RSVG )

README.md

@@ -64,7 +64,6 @@ tint2 is a simple panel/taskbar made for modern X window managers. It was specif
   * Graphical glitches on Intel graphics cards can be avoided by changing the acceleration method to UXA ([issue 595](https://gitlab.com/o9000/tint2/issues/595))
   * Window managers that do not follow exactly the EWMH specification might not interact well with tint2 ([issue 627](https://gitlab.com/o9000/tint2/issues/627)).
   * Full transparency requires a compositor such as Compton (if not provided already by the window manager, as in Compiz/Unity, KDE or XFCE).
-  * As of version 16.0, tint2 requires a C11 compiler (such as GCC version 4.9 or newer).
 
 # How can I help out?
 

src/util/print.h

@@ -1,6 +1,8 @@
 #ifndef PRINT_H
 #define PRINT_H
 
+#ifdef HAS_GENERIC
+
 int print_uchar(unsigned char v);
 
 int print_char(char v);
@@ -52,4 +54,8 @@ int print_unknown();
     void *: print_pointer, \
     default : print_unknown)(x)
 
+#else
+#define print(...) printf("Omitted, the compiler does not support C11 generics.\n")
+#endif
+
 #endif

src/util/test.c

@@ -151,3 +151,9 @@ TEST(dummy) {
     int y = 2;
     ASSERT_EQUAL(x, y);
 }
+
+TEST(dummyBad) {
+    int x = 2;
+    int y = 3;
+    ASSERT_EQUAL(x, y);
+}