Force en_US locale for certain tests.

--- maildrop-3.0.0/libs/maildrop/Makefile.am
+++ maildrop-3.0.0/libs/maildrop/Makefile.am
@@ -71,8 +71,10 @@
 	maildrop.lsm testsuite.txt.idn testsuite2
 
 check-am: testsuite
+if HAS_EN_US
 	VALGRIND="`which valgrind 2>/dev/null`"; export VALGRIND; @SHELL@ ./testsuite >testsuite.diff || exit 1; diff -U 3 testsuite.diff $(srcdir)/testsuite.txt.idn || exit 1; rm -f testsuite.diff
 	VALGRIND="`which valgrind 2>/dev/null`"; export VALGRIND; @SHELL@ $(srcdir)/testsuite2
+endif
 
 noinst_DATA=maildrop.html maildrop.1 maildropfilter.html maildropfilter.7 \
 	maildropgdbm.html maildropgdbm.7
--- maildrop-3.0.0/libs/maildrop/configure.ac
+++ maildrop-3.0.0/libs/maildrop/configure.ac
@@ -201,6 +201,15 @@
 AC_DEFINE_UNQUOTED(MAXLONGSIZE, $MAXLONGSIZE,
 				[ Maximum character size of a long ])
 
+dnl check for en_US locale
+check_en_US() {
+	locale -a | grep en_US.utf8 > /dev/null
+	return $?
+}
+AC_MSG_CHECKING([for en_US.utf8])
+AM_CONDITIONAL([HAS_EN_US], [check_en_US])
+AM_COND_IF([HAS_EN_US],[AC_MSG_RESULT([yes])],[AC_MSG_RESULT([not found])])
+
 dnl Checks for library functions.
 
 AC_FUNC_CLOSEDIR_VOID
--- maildrop-3.0.0/libs/rfc2045/Makefile.am
+++ maildrop-3.0.0/libs/rfc2045/Makefile.am
@@ -84,7 +84,10 @@
 endif
 
 check-am:
+if HAS_EN_US
 	@SHELL@ $(srcdir)/testsuite | cmp -s - $(srcdir)/$(TESTSUITE)
 	@SHELL@ $(srcdir)/testsuitemm | cmp -s - $(srcdir)/testsuitemm.txt
 	@SHELL@ $(srcdir)/testrfc3676parsersuite | diff -U 3 $(srcdir)/testrfc3676parsersuite.txt -
 	./testrfc6533parser
+endif
+
--- maildrop-3.0.0/libs/rfc2045/configure.ac
+++ maildrop-3.0.0/libs/rfc2045/configure.ac
@@ -62,6 +62,15 @@
 AC_CHECK_FUNC(strncasecmp,,CFLAGS="$CFLAGS -Dstrncasecmp=strnicmp")
 AC_CHECK_FUNC(strcasecmp,,CFLAGS="$CFLAGS -Dstrcasecmp=stricmp")
 
+dnl check for en_US locale
+check_en_US() {
+	locale -a | grep en_US.utf8 > /dev/null
+	return $?
+}
+AC_MSG_CHECKING([for en_US.utf8])
+AM_CONDITIONAL([HAS_EN_US], [check_en_US])
+AM_COND_IF([HAS_EN_US],[AC_MSG_RESULT([yes])],[AC_MSG_RESULT([not found])])
+
 AC_ARG_WITH(package, [], package="$withval",
 	[
 		package="$PACKAGE"