Avoid false positive in sc_tests_plain_make maintainer-check.

[Ralf Wildenhues]

I'm seeing this in master now:

../automake/tests/remake11.test:makefiles_am_list=`find . -name Makefile.am | 
LC_ALL=C sort`
../automake/tests/remake11.test:makefiles_list=`echo "$makefiles_am_list" | sed 
's/\.am$//'`
Do not run "make" in the above tests.  Use "$MAKE" instead.
Makefile:1090: recipe for target `sc_tests_plain_make' failed
make: *** [sc_tests_plain_make] Error 1

Merging the patch below in the tests-remake-extend branch to avoid it.

Thanks,
Ralf

    Avoid false positive in sc_tests_plain_make maintainer-check.
    
    * Makefile.am (sc_tests_plain_make): Ensure to only match full
    `make' words.  Avoid false positive with remake11.test.

diff --git a/Makefile.am b/Makefile.am
index ae096cb..15aa3b3 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -342,7 +342,7 @@ sc_tests_make_without_am_makeflags:
 
 ## Tests should never call make directly.
 sc_tests_plain_make:
-       @if grep -v '^#' $(srcdir)/tests/*.test | grep ':[      ]*make'; then \
+       @if grep -v '^#' $(srcdir)/tests/*.test | $(EGREP) ':[  ]*make( |$$)'; 
then \
          echo 'Do not run "make" in the above tests.  Use "$$MAKE" instead.' 
1>&2; \
          exit 1; \
        fi
diff --git a/Makefile.in b/Makefile.in
index 04d7067..1c1bf81 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -1087,7 +1087,7 @@ sc_tests_make_without_am_makeflags:
        fi
 
 sc_tests_plain_make:
-       @if grep -v '^#' $(srcdir)/tests/*.test | grep ':[      ]*make'; then \
+       @if grep -v '^#' $(srcdir)/tests/*.test | $(EGREP) ':[  ]*make( |$$)'; 
then \
          echo 'Do not run "make" in the above tests.  Use "$$MAKE" instead.' 
1>&2; \
          exit 1; \
        fi