--- a/testsuite/testsuite_support/__init__.py	2019-06-09 12:47:22.832308224 +0200
+++ b/testsuite/testsuite_support/__init__.py	2019-06-09 12:48:27.768399377 +0200
@@ -126,8 +126,10 @@
         # Build Langkit_Support so that each testcase does not try to build it
         # in parallel.
         if not self.global_env['options'].disable_tear_up_builds:
-            gargs = ['-p', '-P', self.langkit_support_project_file]
+            gargs = ['-p']
+            gargs = gargs + ['-XGPR_BUILD=relocatable']
+            gargs = gargs + ['-P', self.langkit_support_project_file]
-            cargs = ['-cargs', '-O0', '-g', '-gnatwae']
+            cargs = ['-cargs', '-O0', '-g', '-gnatwa']
             if self.coverage_enabled:
                 gargs.append('--subdirs=gnatcov')
                 cargs.extend(['-fdump-scos', '-fpreserve-control-flow'])
--- a/langkit/support/langkit_support.gpr	2019-06-09 14:00:50.239979207 +0200
+++ b/langkit/support/langkit_support.gpr	2019-06-09 14:00:56.580879634 +0200
@@ -8,7 +8,7 @@
    for Object_Dir use "obj";
 
    package Compiler is
-      for Default_Switches ("Ada") use ("-gnatwae", "-gnatyg");
+      for Default_Switches ("Ada") use ("-gnatws", "-gnatyg");
    end Compiler;
 
 end Langkit_Support;
--- a/langkit/templates/langkit_support_gpr.mako	2019-06-09 19:07:51.131902613 +0200
+++ b/langkit/templates/langkit_support_gpr.mako	2019-06-09 19:09:55.530096368 +0200
@@ -61,7 +61,7 @@
       case Build_Mode is
          when "dev" =>
             for Default_Switches ("Ada") use
-               Common_Ada_Cargs & ("-g", "-O0", "-gnatwe", "-gnata");
+               Common_Ada_Cargs & ("-g", "-O0", "-gnatws", "-gnata");
 
          when "prod" =>
             --  Debug information is useful even with optimization for
--- a/testsuite/testsuite_support/base_driver.py	2019-06-09 20:00:21.202461893 +0200
+++ b/testsuite/testsuite_support/base_driver.py	2019-06-09 20:01:04.516848550 +0200
@@ -327,7 +327,9 @@
 
         :param str project_file: Project file name.
         """
-        argv = ['gprbuild', '-P', project_file, '-p']
+        argv = ['gprbuild']
+        argv = argv + ['-XGPR_BUILD=relocatable']
+        argv = argv + ['-P', project_file, '-p']
         cargs = ['-O0', '-g', '-gnata']
         if self.coverage_enabled:
             argv.append('--subdirs=gnatcov')
--- a/langkit/libmanage.py	2019-06-09 20:40:14.885582672 +0200
+++ b/langkit/libmanage.py	2019-06-09 20:41:13.991738858 +0200
@@ -745,6 +745,7 @@
         result = ['-XBUILD_MODE={}'.format(build_mode),
                   '-XLIBRARY_TYPE={}'.format(library_type),
                   '-XGPR_BUILD={}'.format(library_type),
+                  '-XGNATCOLL_GMP_BUILD={}'.format(library_type),
                   '-XXMLADA_BUILD={}'.format(library_type)]
 
         enable_build_warnings = getattr(args, 'enable_build_warnings', False)
--- a/testsuite/tests/misc/link_two_libs/test.yaml	2019-06-17 09:38:34.796029233 +0200
+++ b/testsuite/tests/misc/link_two_libs/test.yaml	2019-06-17 09:39:06.805549633 +0200
@@ -1,7 +1,3 @@
 driver: python
 input_sources: []
-expect_failure:
-  - if: [gnat_community_2018]
-    then: >
-      A known issue in the gprbuild furnished with GNAT Community 2018
-      prevents this test from passing.
+expect_failure: Gentoo failure