--- gprbuild-gpl-2016-src/Makefile.in.old	2017-01-19 19:52:41.242907252 +0100
+++ gprbuild-gpl-2016-src/Makefile.in	2017-01-19 19:54:45.822646333 +0100
@@ -25,12 +25,12 @@
 host=@host@
 target=@target@
 build=@build@
-prefix=@prefix@
+prefix=$(DESTDIR)@prefix@
 srcdir=@srcdir@
 objdir=@objdir@
 exec_prefix=@exec_prefix@
 datarootdir=@datarootdir@
-datadir=@datadir@
+datadir=$(DESTDIR)@datadir@
 bindir=@bindir@
 libdir=@libdir@
 libexecdir=@libexecdir@
@@ -173,13 +173,13 @@
 libgpr.build: $(foreach t, $(LIBGPR_TYPES), libgpr.build.$(t))
 
 libgpr.build.shared:
-	${BUILDER} -XLIBRARY_TYPE=relocatable -P$(srcdir)/gpr/gpr.gpr
+	${BUILDER} -XLIBRARY_TYPE=relocatable -P$(srcdir)/gpr/gpr.gpr -cargs:Ada $(ADAFLAGS)
 
 libgpr.build.static:
-	${BUILDER} -XLIBRARY_TYPE=static -P$(srcdir)/gpr/gpr.gpr
+	${BUILDER} -XLIBRARY_TYPE=static -P$(srcdir)/gpr/gpr.gpr -cargs:Ada $(ADAFLAGS)
 
 libgpr.build.static-pic:
-	${BUILDER} -XLIBRARY_TYPE=static-pic -P$(srcdir)/gpr/gpr.gpr
+	${BUILDER} -XLIBRARY_TYPE=static-pic -P$(srcdir)/gpr/gpr.gpr -cargs:Ada $(ADAFLAGS)
 
 libgpr.install: $(foreach t, $(LIBGPR_TYPES), libgpr.install.$(t))
 
--- gprbuild-gpl-2016-src/gpr/src/gpr-env.adb.old	2017-11-13 22:16:53.349083426 +0100
+++ gprbuild-gpl-2016-src/gpr/src/gpr-env.adb	2017-11-13 22:17:22.692590351 +0100
@@ -1948,6 +1948,8 @@
 
       end if;
 
+      Add_Directories (Self, "/usr/share/gpr");
+
       if Gpr_Prj_Path.all /= "" then
          Add_Directories (Self, Gpr_Prj_Path.all);
       end if;
--- gprbuild-gpl-2017-src/gpr/src/gpr-names.ads.old	2017-11-19 13:09:18.947527738 +0100
+++ gprbuild-gpl-2017-src/gpr/src/gpr-names.ads	2017-11-19 13:10:08.125654595 +0100
@@ -27,6 +27,8 @@
    Name_Buffer : String (1 .. 1_000_000);
    Name_Len    : Natural := 0;
 
+   Last_Id     : Name_Id := Name_Id'First;
+
    procedure Get_Name_String (Id : Name_Id);
    procedure Get_Name_String (Id : Unit_Name_Type);
    procedure Get_Name_String (Id : File_Name_Type);
--- gprbuild-gpl-2017-src/gpr/src/gpr-names.adb.old	2017-11-19 13:10:27.674316703 +0100
+++ gprbuild-gpl-2017-src/gpr/src/gpr-names.adb	2017-11-19 13:14:38.360963627 +0100
@@ -354,6 +354,8 @@
 
       Name_Chars.Append (ASCII.NUL);
 
+      Last_Id := Name_Entries.Last;
+
       return Name_Entries.Last;
    end Name_Enter;
 
@@ -427,6 +429,8 @@
 
       Name_Chars.Append (ASCII.NUL);
 
+      Last_Id := Name_Entries.Last;
+
       return Name_Entries.Last;
    end Name_Find;
 
--- gprbuild-gpl-2017-src/gpr/src/gpr-snames.adb.old	2017-11-19 13:12:41.592995718 +0100
+++ gprbuild-gpl-2017-src/gpr/src/gpr-snames.adb	2017-11-19 13:16:31.980979696 +0100
@@ -53,6 +53,10 @@
          return;
       end if;
 
+      if Last_Id = Name_Id'First then
+         Add_Name ("");
+      end if;
+
       Add_Name ("a");
       Add_Name ("b");
       Add_Name ("c");