qt-bugs@ issue : 199610
Trolltech task ID : 
bugs.kde.org number : 
applied: no
author: Benjamin Reed <rangerrick@befunk.com>

I don't have the exact output anymore (I've since patched Qt's configure) but
essentially, since I have pcre.h in /opt/kde4-deps/include, it was
conflicting with Qt's (modified) pcre.h in the WebKit bits, since
-I /opt/kde4-deps/include ends up in CXXFLAGS in the generated makefiles, it
comes *before* the specific locations in INCPATH on the compile line, and you
end up with a conflict with the system-installed pcre.h.

Presumably, if your pcre.h is in /usr/include as on most Linux systems, you
wouldn't notice this issue since /usr/include's already in your include path
and people likely don't pass -I /usr/include to configure.  I suspect that on
any platform with a regular, system-installed pcre.h (or clucene headers),
adding -I /usr/include would exhibit this bug, just as a custom-installed
pcre/clucene in another root would.

This patch adds support for using -isystem to allow putting an include
directory at the end of the compiler's header search path.


Index: configure
===================================================================
--- configure	(revision 777050)
+++ configure	(working copy)
@@ -811,6 +811,11 @@
             VAL=`echo $1 | sed 's,-D,,'`
         fi
         ;;
+    -isystem)
+        VAR="add_isystempath"
+        shift
+        VAL="$1"
+        ;;
     -I?*|-I)
         VAR="add_ipath"
         if [ "$1" = "-I" ]; then
@@ -1666,6 +1671,9 @@
     add_ipath)
         I_FLAGS="$I_FLAGS -I\"${VAL}\""
         ;;
+    add_isystempath)
+        I_FLAGS="$I_FLAGS -isystem \"${VAL}\""
+        ;;
     add_lpath)
         L_FLAGS="$L_FLAGS -L\"${VAL}\""
         ;;