make: allow :::= macro assignment on command line

GNU make and bmake have different implementations for := macro
assignment.  In POSIX 202X these are supported by the forms ::=
and :::= respectively.  Only the former was supported on the
pdpmake command line.

Add the required support in process_macros() and update the usage
message.

Adds 48-64 bytes.

2 files changed, 52 insertions, 16 deletions

diff --git a/miscutils/make.c b/miscutils/make.c
index a4fecd640..8d5664500 100644
--- a/miscutils/make.c
+++ b/miscutils/make.c
@@ -51,10 +51,10 @@
 
 //usage:#define make_trivial_usage
 //usage:        IF_FEATURE_MAKE_POSIX(
-//usage:       "[--posix] [-C DIR] [-f FILE] [-j NUM] [-x PRAG] [-eiknpqrsSt] [MACRO[::]=VAL]... [TARGET]..."
+//usage:       "[--posix] [-C DIR] [-f FILE] [-j NUM] [-x PRAG] [-eiknpqrsSt] [MACRO[::[:]]=VAL]... [TARGET]..."
 //usage:        )
 //usage:        IF_NOT_FEATURE_MAKE_POSIX(
-//usage:       "[-C DIR] [-f FILE] [-j NUM] [-eiknpqrsSt] [MACRO[::]=VAL]... [TARGET]..."
+//usage:       "[-C DIR] [-f FILE] [-j NUM] [-eiknpqrsSt] [MACRO[::[:]]=VAL]... [TARGET]..."
 //usage:        )
 //usage:#define make_full_usage "\n\n"
 //usage:       "Maintain files based on their dependencies\n"
@@ -2837,12 +2837,14 @@ expand_makeflags(void)
 static char **
 process_macros(char **argv, int level)
 {
-        char *p;
+        char *equal;
 
         for (; *argv; argv++) {
+                char *colon = NULL;
                 int idx, immediate = 0;
+                int except_dollar = FALSE;
 
-                if (!(p = strchr(*argv, '='))) {
+                if (!(equal = strchr(*argv, '='))) {
                         // Skip targets on the command line
                         if (!posix && level == 1)
                                 continue;
@@ -2851,13 +2853,23 @@ process_macros(char **argv, int level)
                                 break;
                 }
 
-                if (p - 2 > *argv && p[-1] == ':' && p[-2] == ':') {
+                if (equal - 2 > *argv && equal[-1] == ':' && equal[-2] == ':') {
                         if (POSIX_2017)
                                 error("invalid macro assignment");
-                        immediate = M_IMMEDIATE;
-                        p[-2] = '\0';
+                        if (equal - 3 > *argv  && equal[-3] == ':') {
+                                // BSD-style ':='.  Expand RHS, but not '$$',
+                                // resulting macro is delayed expansion.
+                                colon = equal - 3;
+                                except_dollar = TRUE;
+                        } else {
+                                // GNU-style ':='. Expand RHS, including '$$',
+                                // resulting macro is immediate expansion.
+                                colon = equal - 2;
+                                immediate = M_IMMEDIATE;
+                        }
+                        *colon = '\0';
                 } else
-                        *p = '\0';
+                        *equal = '\0';
 
                 /* We want to process _most_ macro assignments.
                  * There are exceptions for particular values from the
@@ -2866,18 +2878,18 @@ process_macros(char **argv, int level)
                 if (!(level == 3 &&
                                 (idx == MAKEFLAGS || idx == SHELL ||
                                         (idx == CURDIR && !useenv && !POSIX_2017)))) {
-                        if (immediate) {
-                                char *exp = expand_macros(p + 1, FALSE);
+                        if (colon) {
+                                char *exp = expand_macros(equal + 1, except_dollar);
                                 setmacro(*argv, exp, level | immediate);
                                 free(exp);
-                        } else {
-                                setmacro(*argv, p + 1, level);
-                        }
+                        } else
+                                setmacro(*argv, equal + 1, level);
                 }
 
-                *p = '=';
-                if (immediate)
-                        p[-2] = ':';
+                if (colon)
+                        *colon = ':';
+                else
+                        *equal = '=';
         }
         return argv;
 }
diff --git a/testsuite/make.tests b/testsuite/make.tests
index bac673178..0397ab4de 100755
--- a/testsuite/make.tests
+++ b/testsuite/make.tests
@@ -176,6 +176,30 @@ target:
         @echo $(reset)
 '
 
+# Since GNU make and bmake interpret := macro assignments differently,
+# POSIX has ::= for the GNU variant and :::= for BSD.
+testing "make different styles of := macro assignment" \
+        "make -f -" \
+        '65 a a $A\n' "" '
+A = a
+GNU ::= $A
+BSD1 :::= $A
+BSD2 :::= $$A
+A = 65
+
+target:
+        @echo '\''$(A) $(GNU) $(BSD1) $(BSD2)'\''
+'
+
+# Similar to the above but for macro assignments on the command line.
+# POSIX has ::= for the GNU variant and :::= for BSD.
+testing "make := macro assignment on command line" \
+        "make -f - A=a 'GNU::=\$A' 'BSD1:::=\$A' 'BSD2:::=\$\$A' A=65" \
+        '65 a a $A\n' "" '
+target:
+        @echo '\''$(A) $(GNU) $(BSD1) $(BSD2)'\''
+'
+
 # basic pattern macro expansion
 testing "make basic pattern macro expansion" \
         "make -f -" \