1Index: mingw-w64-headers/Makefile.am
2===================================================================
3--- mingw-w64-headers/Makefile.am	(revision 5578)
4+++ mingw-w64-headers/Makefile.am	(working copy)
5@@ -118,10 +118,14 @@
6 BUILT_SOURCES = $(IDL_SRCS:.idl=.h)
7
8 .idl.h: crt/_mingw.h
9-	$(WIDL) -DBOOL=WINBOOL -I$(srcdir)/include -I$(srcdir)/direct-x/include -Icrt -I$(srcdir)/crt -h -o $(srcdir)/$@ $<
10+	$(WIDL) -DBOOL=WINBOOL -I$(srcdir)/include -I$(srcdir)/direct-x/include -Icrt -I$(srcdir)/crt -h -o $@ $<
11
12+if SRCDIR_NEQ_BUILDDIR
13+$(warning "srcdir != builddir, debugging comments in idl files will be sub-optimal")
14 endif
15
16+endif
17+
18 _mingw_directx.h: $(srcdir)/crt/sdks/_mingw_directx.h.in
19 	$(SED) s/MINGW_HAS_DX$$/@MINGW_HAS_DX@/ $< > $@
20
21Index: mingw-w64-headers/Makefile.in
22===================================================================
23--- mingw-w64-headers/Makefile.in	(revision 5578)
24+++ mingw-w64-headers/Makefile.in	(working copy)
25@@ -1016,8 +1016,10 @@
26 	find $(distdir) -name ".svn" -type d -delete
27
28 @HAVE_WIDL_TRUE@.idl.h: crt/_mingw.h
29-@HAVE_WIDL_TRUE@	$(WIDL) -DBOOL=WINBOOL -I$(srcdir)/include -I$(srcdir)/direct-x/include -Icrt -I$(srcdir)/crt -h -o $(srcdir)/$@ $<
30+@HAVE_WIDL_TRUE@	$(WIDL) -DBOOL=WINBOOL -I$(srcdir)/include -I$(srcdir)/direct-x/include -Icrt -I$(srcdir)/crt -h -o $@ $<
31
32+@HAVE_WIDL_TRUE@@SRCDIR_NEQ_BUILDDIR_TRUE@$(warning "srcdir != builddir, debugging comments in idl files will be sub-optimal")
33+
34 _mingw_directx.h: $(srcdir)/crt/sdks/_mingw_directx.h.in
35 	$(SED) s/MINGW_HAS_DX$$/@MINGW_HAS_DX@/ $< > $@
36
37Index: mingw-w64-headers/configure
38===================================================================
39--- mingw-w64-headers/configure	(revision 5578)
40+++ mingw-w64-headers/configure	(working copy)
41@@ -617,6 +617,8 @@
42 build_vendor
43 build_cpu
44 build
45+SRCDIR_NEQ_BUILDDIR_FALSE
46+SRCDIR_NEQ_BUILDDIR_TRUE
47 MAINT
48 MAINTAINER_MODE_FALSE
49 MAINTAINER_MODE_TRUE
50@@ -2310,6 +2312,16 @@
51
52
53
54+# Check so we can warn about this.
55+ if test ! "$srcdir" = "$builddir"; then
56+  SRCDIR_NEQ_BUILDDIR_TRUE=
57+  SRCDIR_NEQ_BUILDDIR_FALSE='#'
58+else
59+  SRCDIR_NEQ_BUILDDIR_TRUE='#'
60+  SRCDIR_NEQ_BUILDDIR_FALSE=
61+fi
62+
63+
64 # Make sure we can run config.sub.
65 $SHELL "$ac_aux_dir/config.sub" sun4 >/dev/null 2>&1 ||
66   as_fn_error $? "cannot run $SHELL $ac_aux_dir/config.sub" "$LINENO" 5
67@@ -2831,6 +2843,10 @@
68   as_fn_error $? "conditional \"MAINTAINER_MODE\" was never defined.
69 Usually this means the macro was only invoked conditionally." "$LINENO" 5
70 fi
71+if test -z "${SRCDIR_NEQ_BUILDDIR_TRUE}" && test -z "${SRCDIR_NEQ_BUILDDIR_FALSE}"; then
72+  as_fn_error $? "conditional \"SRCDIR_NEQ_BUILDDIR\" was never defined.
73+Usually this means the macro was only invoked conditionally." "$LINENO" 5
74+fi
75 if test -z "${HAVE_WIDL_TRUE}" && test -z "${HAVE_WIDL_FALSE}"; then
76   as_fn_error $? "conditional \"HAVE_WIDL\" was never defined.
77 Usually this means the macro was only invoked conditionally." "$LINENO" 5
78Index: mingw-w64-headers/configure.ac
79===================================================================
80--- mingw-w64-headers/configure.ac	(revision 5578)
81+++ mingw-w64-headers/configure.ac	(working copy)
82@@ -10,6 +10,9 @@
83 AM_INIT_AUTOMAKE([foreign])
84 AM_MAINTAINER_MODE
85
86+# Check so we can warn about this.
87+AM_CONDITIONAL([SRCDIR_NEQ_BUILDDIR],[test ! "$srcdir" = "$builddir"])
88+
89 AC_CANONICAL_HOST
90
91 # Checks for programs.
92