[Savannah #20501] Handle adding -r/-R to MAKEFLAGS in the makefile.

If -R is set in the makefile and not the command line, then go through all the
default variables and undefine them.  If -r is set in the makefile and not in
the command line, then remove all .SUFFIX prefixes (unless the user set it)
and SUFFIX variable setting.  In -p mode don't print builtins.

1 files changed, 24 insertions, 4 deletions

diff --git a/main.c b/main.c
index 8eed56d..5823840 100644
--- a/main.c
+++ b/main.c
@@ -1767,13 +1767,33 @@ main (int argc, char **argv, char **envp)
   }
 #endif /* __MSDOS__ || __EMX__ */
 
-  /* Decode switches again, in case the variables were set by the makefile.  */
-  decode_env_switches (STRING_SIZE_TUPLE ("GNUMAKEFLAGS"));
-  decode_env_switches (STRING_SIZE_TUPLE ("MAKEFLAGS"));
+  {
+    int old_builtin_rules_flag = no_builtin_rules_flag;
+    int old_builtin_variables_flag = no_builtin_variables_flag;
+
+    /* Decode switches again, for variables set by the makefile.  */
+    decode_env_switches (STRING_SIZE_TUPLE ("GNUMAKEFLAGS"));
+    decode_env_switches (STRING_SIZE_TUPLE ("MAKEFLAGS"));
 #if 0
-  decode_env_switches (STRING_SIZE_TUPLE ("MFLAGS"));
+    decode_env_switches (STRING_SIZE_TUPLE ("MFLAGS"));
 #endif
 
+    /* If we've disabled builtin rules, get rid of them.  */
+    if (no_builtin_rules_flag && ! old_builtin_rules_flag)
+      {
+        if (suffix_file->builtin)
+          {
+            free_dep_chain (suffix_file->deps);
+            suffix_file->deps = 0;
+          }
+        define_variable_cname ("SUFFIXES", "", o_default, 0);
+      }
+
+    /* If we've disabled builtin variables, get rid of them.  */
+    if (no_builtin_variables_flag && ! old_builtin_variables_flag)
+      undefine_default_variables ();
+  }
+
 #if defined (__MSDOS__) || defined (__EMX__)
   if (job_slots != 1
 # ifdef __EMX__