From c635f46439ba36088773bc6d5991c50e1d8e4e38 Mon Sep 17 00:00:00 2001
From: o9000 <mrovi9000@gmail.com>
Date: Wed, 20 Dec 2017 18:55:50 +0100
Subject: [PATCH] Feature test C11 generics, since GCC lies about compliance

---
 CMakeLists.txt   | 8 ++++++++
 README.md        | 1 -
 src/util/print.h | 6 ++++++
 src/util/test.c  | 6 ++++++
 4 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8f28cc5..46dd7b9 100644
--- a/CMakeLists.txt
+++ b/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 )
diff --git a/README.md b/README.md
index 2608b5d..eaca8ea 100644
--- a/README.md
+++ b/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?
 
diff --git a/src/util/print.h b/src/util/print.h
index 52ac060..20ff81a 100644
--- a/src/util/print.h
+++ b/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
diff --git a/src/util/test.c b/src/util/test.c
index d375a0d..9cf3473 100644
--- a/src/util/test.c
+++ b/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);
+}