diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index ebd9f3cb4c1..b56de568726 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,8 @@
+2015-12-06  Eric Botcazou  <ebotcazou@adacore.com>
+
+	PR ada/50048
+	* gcc-interface/Makefile.in (INCLUDES): Use -iquote.
+
 2015-12-06  Eric Botcazou  <ebotcazou@adacore.com>
 
 	PR ada/56274
diff --git a/gcc/ada/gcc-interface/Makefile.in b/gcc/ada/gcc-interface/Makefile.in
index c5e6b3013e2..8d91b667087 100644
--- a/gcc/ada/gcc-interface/Makefile.in
+++ b/gcc/ada/gcc-interface/Makefile.in
@@ -257,7 +257,8 @@ TOOLS_LIBS += @NO_PIE_FLAG@
 # Both . and srcdir are used, in that order,
 # so that tm.h and config.h will be found in the compilation
 # subdirectory rather than in the source directory.
-INCLUDES = -I- -I. -I.. -I$(srcdir)/ada -I$(srcdir) -I$(ftop_srcdir)/include $(GMPINC)
+INCLUDES = -iquote . -iquote .. -iquote $(srcdir)/ada -iquote $(srcdir) \
+	   -I $(ftop_srcdir)/include $(GMPINC)
 
 ADA_INCLUDES = -I- -I. -I$(srcdir)/ada
 
diff --git a/gnattools/ChangeLog b/gnattools/ChangeLog
index 4daff874eb1..bdcd968f308 100644
--- a/gnattools/ChangeLog
+++ b/gnattools/ChangeLog
@@ -1,3 +1,9 @@
+2015-12-06  Eric Botcazou  <ebotcazou@adacore.com>
+
+	PR ada/50048
+	* Makefile.in (ftop_srcdir): New variable.
+	(INCLUDES_FOR_SUBDIR): Use -iquote and $(ftop_srcdir).
+
 2015-06-08  John Marino  <gnugcc@marino.st>
 
 	* configure.ac (*-*-dragonfly*): New configuration.
diff --git a/gnattools/Makefile.in b/gnattools/Makefile.in
index 423cc6e950c..0c889eeec7b 100644
--- a/gnattools/Makefile.in
+++ b/gnattools/Makefile.in
@@ -57,12 +57,16 @@ ADAFLAGS= -gnatpg -gnata
 # For finding the GCC build dir, which is used far too much
 GCC_DIR=../gcc
 
+# Full path to top source directory
+ftop_srcdir := $(shell cd $(srcdir)/..;${PWD_COMMAND})
+
 # Absolute srcdir for gcc (why do we want absolute?  I dunno)
 fsrcdir := $(shell cd $(srcdir)/../gcc/; ${PWD_COMMAND})
 
 # Useful "subroutines" for the excess includes
-INCLUDES_FOR_SUBDIR = -I. -I.. -I../.. -I$(fsrcdir)/ada -I$(fsrcdir)/config \
-	-I$(fsrcdir)/../include -I$(fsrcdir)
+INCLUDES_FOR_SUBDIR = -iquote . -iquote .. -iquote ../.. \
+		      -iquote $(fsrcdir)/ada -iquote $(fsrcdir)/config \
+		      -iquote $(fsrcdir) -I$(ftop_srcdir)/include
 ADA_INCLUDES_FOR_SUBDIR = -I. -I$(fsrcdir)/ada
 
 CXX_LFLAGS = \