wcc/cgen: #154 str==-global ident operand — name(SB) base in cbinop, not (BP) garbage (cstage)

The str==/!= arm of cbinop had an N_IDENT fast-path that assumed the operand
was a local: localfind returns 0 for a module-global str, so it loaded
(BP)/8(BP) — saved-BP/retaddr garbage — into rt_streq. `p == sepstr` silently
compared garbage (returned wrong). Mirror #148's global branch at both sub-sites
(rhs/lhs): off==0 && let_islet -> LEAQ name(SB) base, load ptr/len. Distinct
per-site fast-path, not a shared choke (the by-value-global-arg family
#148/#150/#151 closes separately). cstage-only; the wwstage str== twin is #146
(-> #125 batch).

Pin test/wcc/989_strglobeq (table-driven: const+let globals, rhs+lhs ident,
==/!=, unequal + len>1 rows; teeth-proven). Surfaced by the lib/path c3
buffer-ops gate-1 oracle.

test/wcc/989_strglobeq_run.c

@@ -0,0 +1,51 @@
+/*
+ * 989_strglobeq_run — #154 regression pin. Compile + run the strglobeq
+ * fixture under the C-side `ww run` driver (cstage w6c) and assert exit 0.
+ *
+ * The bug (str== fast-path read the global str header off BP+0 instead of
+ * name(SB)) is a CSTAGE silent miscompile; byte-id 990-997 can't see a
+ * runtime-value miscompile, so only this value check catches it. Same
+ * thin-wrapper shape as 989_letshadow_run.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/wait.h>
+
+static int
+runwait(const char *cmd)
+{
+	int rc = system(cmd);
+	if (rc == -1) return -1;
+	if (WIFEXITED(rc)) return WEXITSTATUS(rc);
+	return 1;
+}
+
+int
+main(void)
+{
+	const char *bin = getenv("BIN");
+	if (!bin) bin = "out/bin";
+	char absbin[1024];
+	if (bin[0] != '/') {
+		char cwd[1024];
+		if (getcwd(cwd, sizeof cwd) == NULL) return 1;
+		snprintf(absbin, sizeof absbin, "%s/%s", cwd, bin);
+		bin = absbin;
+	}
+	char cwd[1024];
+	if (getcwd(cwd, sizeof cwd) == NULL) return 1;
+
+	const char *src = "test/wcc/989_strglobeq.ww";
+	char path[1024], cmd[2048];
+	snprintf(path, sizeof path, "%s/%s", cwd, src);
+	snprintf(cmd, sizeof cmd, "%s/ww run %s", bin, path);
+	int rc = runwait(cmd);
+	if (rc != 0) {
+		fprintf(stderr, "strglobeq_run FAIL: %s exited %d "
+		    "(row %d miscompiled — #154)\n", src, rc, rc - 10);
+		return 1;
+	}
+	printf("strglobeq_run: %s ok\n", src);
+	return 0;
+}