Have a single top-level main for running unit-tests

Instead of each .c file becoming a self-standing .t executable file,
and being run for executing the unit tests local to the file, now each
.c becomes a .to object (akin to a .o object, but one where the -DTEST
flag is given to the compiler).  After that, all the .to objects are
linked together in a gistatic-tests executable, in a equivalent way
that all .o files get linked together in a gistatic executable.

This change was necessary in order to allow dependencies between
objects.  The next task will be making a tar of a repository tree
checkout, and src/gistatic.{o,to} will start depending on
src/tar.{o,to}.  If each file has its own main function when -DTEST is
given, then I wont be able to link them together.

I took the opportunity that I had to change the Makefile, and I
improved the dependency between targets and dependencies greatly.  From
what I can tell now, it is correct.

1 files changed, 15 insertions, 0 deletions

diff --git a/src/main.c b/src/main.c
index 52c749f..34214ea 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,5 +1,20 @@
+#include "tar.h"
 #include "gistatic.h"
 
+#include <stdlib.h>
+
+#ifdef TEST
+static void unit_tests(void) {
+	unit_tests_tar();
+	unit_tests_gistatic();
+}
+#endif
+
 int main(int argc, char *argv[]) {
+#ifdef TEST
+	unit_tests();
+	return EXIT_SUCCESS;
+#endif
+
 	return gistatic_main(argc, argv);
 }