checkpoint 1990 Makefiles

Added Makefiles for 1990 entries.

In a some cases the source code was modified.

Modified 1990 README.md files.

In some cases the program still cannot be compiled.

1990/stig/stig.sh

@@ -0,0 +1 @@
+alias c="cc -Wno-implicit-int -E -Dc='int main(){printf(\"N%sested comments allowed.\\n"'",/*/*/0*/**/1?"":"o n"'");}' stig.c|grep -v '^#'>o.c;cc -include stdio.h -o o o.c;./o"