workaround to make Qt5 code build with Clang+icecream

Qt5 uses QT_HAS_INCLUDE (which maps to __has_include), and uses it
to guard #include <chrono>. Clang's -frewrite-includes, which icecream
uses for distributing source to remote nodes, for some reason doesn't
recognize __has_include properly when wrapped by this macro, and this
all results in strange compile errors related to std::chrono.

Change-Id: Ia375ebd928b40ebd51ab4cc59488f3b62939e039
Reviewed-on: https://gerrit.libreoffice.org/65506
Tested-by: Jenkins
Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>

vcl/Library_vclplug_kde5.mk

@@ -94,4 +94,12 @@ $(eval $(call gb_Library_add_libs,vclplug_kde5,\
 ))
 endif
 
+# Workaround for clang+icecream (clang's -frewrite-includes
+# doesn't handle Qt5's QT_HAS_INCLUDE that Qt5 uses for <chrono>).
+ifeq ($(COM_IS_CLANG),TRUE)
+$(eval $(call gb_Library_add_defs,vclplug_qt5, \
+    -include chrono \
+))
+endif
+
 # vim: set noet sw=4 ts=4:

vcl/Library_vclplug_qt5.mk

@@ -118,4 +118,12 @@ $(eval $(call gb_Library_add_libs,vclplug_qt5,\
 ))
 endif
 
+# Workaround for clang+icecream (clang's -frewrite-includes
+# doesn't handle Qt5's QT_HAS_INCLUDE that Qt5 uses for <chrono>).
+ifeq ($(COM_IS_CLANG),TRUE)
+$(eval $(call gb_Library_add_defs,vclplug_qt5, \
+    -include chrono \
+))
+endif
+
 # vim: set noet sw=4 ts=4: