make: report POSIX 202X issue with include

Synchronising with upstream pdpmake showed that a test was missing
from the BusyBox port.  POSIX 202X doesn't specify what should
happen if an include statement has no arguments.

When the POSIX 202X standard is being enforced this is reported as
an error.

Adds 32 bytes.

1 files changed, 12 insertions, 6 deletions

diff --git a/miscutils/make.c b/miscutils/make.c
index deb04ec88..8394c4e7b 100644
--- a/miscutils/make.c
+++ b/miscutils/make.c
@@ -750,10 +750,12 @@ is_valid_macro(const char *name)
         for (s = name; *s; ++s) {
                 // In POSIX mode only a limited set of characters are guaranteed
                 // to be allowed in macro names.
-                if (posix &&
-                                ((pragma & P_MACRO_NAME) || !POSIX_2017 ?
-                                        !isfname(*s) : !ispname(*s)))
+                if (posix) {
+                        // Find the appropriate character set
+                        if ((pragma & P_MACRO_NAME) || !POSIX_2017 ?
+                                !isfname(*s) : !ispname(*s))
                         return FALSE;
+                }
                 // As an extension allow anything that can get through the
                 // input parser, apart from the following.
                 if (*s == '=' || isblank(*s) || iscntrl(*s))
@@ -1993,6 +1995,10 @@ input(FILE *fd, int ilevel)
                                 if (p == NULL || gettok(&q)) {
                                         error("one include file per line");
                                 }
+                        } else if (makefile == old_makefile) {
+                                // In POSIX 202X no include file is unspecified behaviour.
+                                if (posix)
+                                        error("no include file");
                         }
 
                         makefile = old_makefile;
@@ -3071,12 +3077,12 @@ int make_main(int argc UNUSED_PARAM, char **argv)
         setmacro("$", "$", 0 | M_VALID);
 
         // Process macro definitions from the command line
-        if (posix)
+        if (!posix)
+                process_macros(argv, 1);
+        else
                 // In POSIX mode macros must appear before targets.
                 // argv should now point to targets only.
                 argv = process_macros(argv, 1);
-        else
-                process_macros(argv, 1);
 
         // Process macro definitions from MAKEFLAGS
         if (fargv) {