[gcc/devel/c++-coroutines] Fix missing dependencies for selftests which occasionally causes failed builds.

[Iain D Sandoe]

https://gcc.gnu.org/g:b19d8aac15649f31a7588b2634411a1922906ea8

commit b19d8aac15649f31a7588b2634411a1922906ea8
Author: Romain Naour <romain.naour@gmail.com>
Date:   Wed Jun 3 12:30:57 2020 -0600

    Fix missing dependencies for selftests which occasionally causes failed builds.
    
    gcc/
    
            * Makefile.in (SELFTEST_DEPS): Move before including language makefile
            fragments.

Diff:
---
 gcc/Makefile.in | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index aab1dbba57b..be11311b60d 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -1735,6 +1735,10 @@ $(FULL_DRIVER_NAME): ./xgcc$(exeext)
 	$(LN_S) $< $@
 
 #
+# SELFTEST_DEPS need to be set before including language makefile fragments.
+# Otherwise $(SELFTEST_DEPS) is empty when used from <LANG>/Make-lang.in.
+SELFTEST_DEPS = $(GCC_PASSES) stmp-int-hdrs $(srcdir)/testsuite/selftests
+
 # Language makefile fragments.
 
 # The following targets define the interface between us and the languages.
@@ -2010,8 +2014,6 @@ DEVNULL=$(if $(findstring mingw,$(build)),nul,/dev/null)
 SELFTEST_FLAGS = -nostdinc $(DEVNULL) -S -o $(DEVNULL) \
 	-fself-test=$(srcdir)/testsuite/selftests
 
-SELFTEST_DEPS = $(GCC_PASSES) stmp-int-hdrs $(srcdir)/testsuite/selftests
-
 # Run the selftests during the build once we have a driver and the frontend,
 # so that self-test failures are caught as early as possible.
 # Use "s-selftest-FE" to ensure that we only run the selftests if the