qt4: add patch for gcc8 issue with alignof()

srcpkgs/qt5/patches/gcc8-chromium-mojo.patch

@@ -0,0 +1,18 @@
+--- qtwebengine/src/3rdparty/chromium/mojo/public/c/system/macros.h	2018-05-15 14:58:46.448912634 -0400
++++ qtwebengine/src/3rdparty/chromium/mojo/public/c/system/macros.h	2018-05-15 14:58:52.041784613 -0400
+@@ -18,7 +18,13 @@
+ #endif
+ 
+ // Like the C++11 |alignof| operator.
+-#if __cplusplus >= 201103L
++#if defined(__GNUC__) && __GNUC__ >= 8
++// GCC 8 has changed the alignof operator to return the minimal alignment
++// required by the target ABI, instead of the preferred alignment.
++// This means that on 32-bit x86, it will return 4 instead of 8.
++// Use __alignof__ instead to avoid this.
++#define MOJO_ALIGNOF(type) __alignof__(type)
++#elif __cplusplus >= 201103L
+ #define MOJO_ALIGNOF(type) alignof(type)
+ #elif defined(__GNUC__)
+ #define MOJO_ALIGNOF(type) __alignof__(type)
+generated by cgit v1.1 at 2018-05-28 17:38:41 +0000