build: Remove hard requirement for GNU .init_array section support

In case the support is not available, just stop building the
libbsd-ctor.a library, which is a nice to have thing, but should not
have been a hard requirement from the start. This should allow to
build libbsd on non-glibc based systems using another libc.

configure.ac

@@ -101,9 +101,8 @@ int main() { return rc; }
 		]
 	)]
 )
-if test "$libbsd_cv_gnu_init_array_support" = no; then
-	AC_MSG_ERROR([missing required GNU .init_array section support])
-fi
+AM_CONDITIONAL([BUILD_LIBBSD_CTOR],
+               [test "$libbsd_cv_gnu_init_array_support" = yes])
 
 # Checks for library functions.
 AC_MSG_CHECKING([for program_invocation_short_name])

src/Makefile.am

@@ -22,12 +22,17 @@ CLEANFILES = \
 pkgconfigdir = $(libdir)/pkgconfig
 pkgconfig_DATA = \
 	libbsd.pc \
-	libbsd-ctor.pc \
 	libbsd-overlay.pc \
 	$(nil)
 
 lib_LTLIBRARIES = libbsd.la
-lib_LIBRARIES = libbsd-ctor.a
+lib_LIBRARIES =
+
+if BUILD_LIBBSD_CTOR
+pkgconfig_DATA += libbsd-ctor.pc
+
+lib_LIBRARIES += libbsd-ctor.a
+endif
 
 hash/md5hl.c: $(srcdir)/hash/helper.c
 	$(AM_V_at) $(MKDIR_P) hash

test/.gitignore

@@ -4,4 +4,5 @@ funopen
 headers
 humanize
 overlay
+proctitle-init
 proctitle

test/Makefile.am

@@ -14,12 +14,19 @@ check_PROGRAMS = \
 	humanize \
 	fgetln \
 	funopen \
-	proctitle \
+	proctitle-init \
 	$(nil)
 
+if BUILD_LIBBSD_CTOR
+check_PROGRAMS += proctitle
+endif
+
 humanize_LDFLAGS = $(top_builddir)/src/libbsd.la
 fgetln_LDFLAGS = $(top_builddir)/src/libbsd.la
 funopen_LDFLAGS = $(top_builddir)/src/libbsd.la
+proctitle_init_SOURCES = proctitle.c
+proctitle_init_CPPFLAGS = $(AM_CPPFLAGS) -DTEST_USE_SETPROCTITLE_INIT=1
+proctitle_init_LDFLAGS = $(top_builddir)/src/libbsd.la
 proctitle_LDFLAGS = \
 	-Wl,-u,libbsd_init_func \
 	$(top_builddir)/src/libbsd-ctor.a \

test/proctitle.c

@@ -31,12 +31,16 @@
 #include <string.h>
 
 int
-main(int argc, char **argv)
+main(int argc, char **argv, char **envp)
 {
 	const char newtitle_base[] = "test arg1 arg2";
 	char *newtitle_full;
 	char *envvar;
 
+#ifdef TEST_USE_SETPROCTITLE_INIT
+	setproctitle_init(argc, argv, envp);
+#endif
+
 	setproctitle("-test %s arg2", "arg1");
 	assert(strcmp(argv[0], newtitle_base) == 0);