make: override commands for single-colon target rule

If more than one single-colon target rule has commands only the
last set of commands should be used.

Previously the presence of more than one single-colon target rule
with commands was treated as an error.

Adds 88-112 bytes.

1 files changed, 30 insertions, 7 deletions

diff --git a/miscutils/make.c b/miscutils/make.c
index a165274aa..8026917b3 100644
--- a/miscutils/make.c
+++ b/miscutils/make.c
@@ -276,6 +276,7 @@ struct globals {
         time_t ar_mtime;
         int lineno;     // Physical line number in file
         int dispno;     // Line number for display purposes
+        struct cmd *curr_cmd;
         const char *rulepos;
         int rule_idx;
 #define IF_MAX 10
@@ -307,6 +308,7 @@ struct globals {
 #define ar_mtime        (G.ar_mtime)
 #define lineno          (G.lineno)
 #define dispno          (G.dispno)
+#define curr_cmd        (G.curr_cmd)
 #define rulepos         (G.rulepos)
 #define rule_idx        (G.rule_idx)
 #define clevel          (G.clevel)
@@ -338,9 +340,20 @@ static struct name *dyndep(struct name *np, struct rule *infrule,
 static void
 vwarning(FILE *stream, const char *msg, va_list list)
 {
+        const char *m = NULL;
+        int d = 0;
+
+        if (curr_cmd) {
+                m = curr_cmd->c_makefile;
+                d = curr_cmd->c_dispno;
+        } else if (makefile) {
+                m = makefile;
+                d = dispno;
+        }
+
         fprintf(stream, "%s: ", applet_name);
-        if (makefile)
-                fprintf(stream, "(%s:%d): ", makefile, dispno);
+        if (m)
+                fprintf(stream, "(%s:%d): ", m, d);
         vfprintf(stream, msg, list);
         fputc('\n', stream);
 }
@@ -726,6 +739,7 @@ addrule(struct name *np, struct depend *dp, struct cmd *cp, int flag)
 {
         struct rule *rp;
         struct rule **rpp;
+        struct cmd *old_cp;
 
         // Can't mix single-colon and double-colon rules
         if (!posix && (np->n_flag & N_TARGET)) {
@@ -742,7 +756,7 @@ addrule(struct name *np, struct depend *dp, struct cmd *cp, int flag)
                 return;
         }
 
-        if (cp && !(np->n_flag & N_DOUBLE) && getcmd(np)) {
+        if (cp && !(np->n_flag & N_DOUBLE) && (old_cp = getcmd(np))) {
                 // Handle the inference rule redefinition case
                 // .DEFAULT rule can also be redefined (as an extension).
                 if ((np->n_flag & N_INFERENCE)
@@ -751,7 +765,17 @@ addrule(struct name *np, struct depend *dp, struct cmd *cp, int flag)
                         freerules(np->n_rule);
                         np->n_rule = NULL;
                 } else {
-                        error("commands defined twice for target %s", np->n_name);
+                        // We're adding commands to a single colon rule which
+                        // already has some.  Clear the old ones first.
+                        warning("overriding rule for target %s", np->n_name);
+                        curr_cmd = old_cp;
+                        warning("previous rule for target %s", np->n_name);
+                        curr_cmd = NULL;
+
+                        for (rp = np->n_rule; rp; rp = rp->r_next) {
+                                freecmds(rp->r_cmd);
+                                rp->r_cmd = NULL;
+                        }
                 }
         }
 
@@ -2602,8 +2626,7 @@ docmds(struct name *np, struct cmd *cp)
                 uint32_t ssilent, signore, sdomake;
 
                 // Location of command in makefile (for use in error messages)
-                makefile = cp->c_makefile;
-                dispno = cp->c_dispno;
+                curr_cmd = cp;
                 opts &= ~OPT_make;      // We want to know if $(MAKE) is expanded
                 q = command = expand_macros(cp->c_cmd, FALSE);
                 ssilent = silent || (np->n_flag & N_SILENT) || dotouch;
@@ -2697,7 +2720,7 @@ docmds(struct name *np, struct cmd *cp)
                 estat = MAKE_DIDSOMETHING;
         }
 
-        makefile = NULL;
+        curr_cmd = NULL;
         return estat;
 }