cmd/dist: respect system CFLAGS/LDFLAGS

Update #6882.

LGTM=rsc
R=golang-codereviews, rsc
CC=golang-codereviews
https://golang.org/cl/69860055

diff --git a/src/cmd/dist/build.c b/src/cmd/dist/build.c
index e79b7188e0fa550cd649d89266c7844b75334197..b3ed471b9c5379c93987c8537dfbb2b3e529e3b6 100644 (file)
--- a/src/cmd/dist/build.c
+++ b/src/cmd/dist/build.c
@@ -27,6 +27,8 @@ char *gochar;
 char *goversion;
 char *slash;   // / for unix, \ for windows
 char *defaultcc;
+char *defaultcflags;
+char *defaultldflags;
 char *defaultcxxtarget;
 char *defaultcctarget;
 bool   rebuildall;
@@ -169,6 +171,12 @@ init(void)
        }
        defaultcc = btake(&b);
 
+       xgetenv(&b, "CFLAGS");
+       defaultcflags = btake(&b);
+
+       xgetenv(&b, "LDFLAGS");
+       defaultldflags = btake(&b);
+
        xgetenv(&b, "CC_FOR_TARGET");
        if(b.len == 0) {
                bprintf(&b, defaultcc);
@@ -465,12 +473,19 @@ static char *proto_gccargs[] = {
        // GCC 4.5.4 (NetBSD nb1 20120916) on ARM is known to mis-optimize gc/mparith3.c
        // Fix available at http://patchwork.ozlabs.org/patch/64562/.
        "-O1",
+#endif
+};
+
+// gccargs2 is the second part of gccargs.
+// it is used if the environment isn't defining CFLAGS.
+static char *proto_gccargs2[] = {
+#if defined(__NetBSD__) && defined(__arm__)
 #else
        "-O2",
 #endif
 };
 
-static Vec gccargs;
+static Vec gccargs, ldargs;
 
 // deptab lists changes to the default dependencies for a given prefix.
 // deps ending in /* read the whole directory; deps beginning with -
@@ -682,10 +697,14 @@ install(char *dir)
 
        // set up gcc command line on first run.
        if(gccargs.len == 0) {
-               bprintf(&b, "%s", defaultcc);
+               bprintf(&b, "%s %s", defaultcc, defaultcflags);
                splitfields(&gccargs, bstr(&b));
                for(i=0; i<nelem(proto_gccargs); i++)
                        vadd(&gccargs, proto_gccargs[i]);
+               if(defaultcflags[0] == '\0') {
+                       for(i=0; i<nelem(proto_gccargs2); i++)
+                               vadd(&gccargs, proto_gccargs2[i]);
+               }
                if(contains(gccargs.p[0], "clang")) {
                        // disable ASCII art in clang errors, if possible
                        vadd(&gccargs, "-fno-caret-diagnostics");
@@ -699,6 +718,10 @@ install(char *dir)
                        vadd(&gccargs, "-mmacosx-version-min=10.6");
                }
        }
+       if(ldargs.len == 0 && defaultldflags[0] != '\0') {
+               bprintf(&b, "%s", defaultldflags);
+               splitfields(&ldargs, bstr(&b));
+       }
 
        islib = hasprefix(dir, "lib") || streq(dir, "cmd/cc") || streq(dir, "cmd/gc");
        ispkg = hasprefix(dir, "pkg");
@@ -742,7 +765,7 @@ install(char *dir)
                targ = link.len;
                vadd(&link, bpathf(&b, "%s/%s%s", tooldir, elem, exe));
        } else {
-               // C command. Use gccargs.
+               // C command. Use gccargs and ldargs.
                if(streq(gohostos, "plan9")) {
                        vadd(&link, bprintf(&b, "%sl", gohostchar));
                        vadd(&link, "-o");
@@ -750,6 +773,7 @@ install(char *dir)
                        vadd(&link, bpathf(&b, "%s/%s", tooldir, name));
                } else {
                        vcopy(&link, gccargs.p, gccargs.len);
+                       vcopy(&link, ldargs.p, ldargs.len);
                        if(sflag)
                                vadd(&link, "-static");
                        vadd(&link, "-o");