3 files changed, 74 insertions, 8 deletions

diff --git a/src/driver/slbt_amain.c b/src/driver/slbt_amain.c
index 48133b0..7d4a5a9 100644
--- a/src/driver/slbt_amain.c
+++ b/src/driver/slbt_amain.c
@@ -56,6 +56,9 @@ static void slbt_perform_driver_actions(struct slbt_driver_ctx * dctx)
 	if (dctx->cctx->drvflags & SLBT_DRIVER_CONFIG)
 		slbt_output_config(dctx);
 
+	if (dctx->cctx->drvflags & SLBT_DRIVER_FEATURES)
+		slbt_output_features(dctx);
+
 	if (dctx->cctx->mode == SLBT_MODE_COMPILE)
 		slbt_exec_compile(dctx,0);
 
diff --git a/src/driver/slbt_driver_ctx.c b/src/driver/slbt_driver_ctx.c
index 2f08895..5b11848 100644
--- a/src/driver/slbt_driver_ctx.c
+++ b/src/driver/slbt_driver_ctx.c
@@ -45,6 +45,10 @@ static const char cfgnmachine[] = "native (derived from -dumpmachine)";
 static const char cfgxmachine[] = "foreign (derived from -dumpmachine)";
 static const char cfgnative[]   = "native";
 
+
+/* default compiler argv */
+static char * slbt_default_cargv[] = {"cc",0};
+
 /* elf rpath */
 static const char*ldrpath_elf[] = {
 	"/lib",
@@ -191,6 +195,7 @@ static int slbt_split_argv(
 	struct argv_entry *		mode;
 	struct argv_entry *		config;
 	struct argv_entry *		finish;
+	struct argv_entry *		features;
 	const struct argv_option **	popt;
 	const struct argv_option **	optout;
 	const struct argv_option *	optv[SLBT_OPTV_ELEMENTS];
@@ -219,24 +224,32 @@ static int slbt_split_argv(
 	}
 
 	/* obtain slibtool's own arguments */
-	compiler = argv[ctx.unitidx];
-	argv[ctx.unitidx] = 0;
+	if (ctx.unitidx) {
+		compiler = argv[ctx.unitidx];
+		argv[ctx.unitidx] = 0;
+
+		meta = argv_get(argv,optv,ARGV_VERBOSITY_NONE);
+		argv[ctx.unitidx] = compiler;
+	} else {
+		meta = argv_get(argv,optv,ARGV_VERBOSITY_NONE);
+	}
 
-	meta = argv_get(argv,optv,ARGV_VERBOSITY_NONE);
-	argv[ctx.unitidx] = compiler;
+	/* missing all of --mode, --config, --features, and --finish? */
+	mode = config = finish = features = 0;
 
-	/* missing all of --mode, --config, and --finish? */
-	for (mode=0, config=0, finish=0, entry=meta->entries; entry->fopt; entry++)
+	for (entry=meta->entries; entry->fopt; entry++)
 		if (entry->tag == TAG_MODE)
 			mode = entry;
 		else if (entry->tag == TAG_CONFIG)
 			config = entry;
 		else if (entry->tag == TAG_FINISH)
 			finish = entry;
+		else if (entry->tag == TAG_FEATURES)
+			features = entry;
 
 	argv_free(meta);
 
-	if (!mode && !config && !finish) {
+	if (!mode && !config && !finish && !features) {
 		fprintf(stderr,
 			"%s: error: --mode must be specified.\n",
 			program);
@@ -244,7 +257,7 @@ static int slbt_split_argv(
 	}
 
 	/* missing compiler? */
-	if (!ctx.unitidx && !finish) {
+	if (!ctx.unitidx && !finish && !features) {
 		if (flags & SLBT_DRIVER_VERBOSITY_ERRORS)
 			fprintf(stderr,
 				"%s: error: <compiler> is missing.\n",
@@ -261,6 +274,16 @@ static int slbt_split_argv(
 	else
 		return -1;
 
+	/* --features and no <compiler>? */
+	if (features && !ctx.unitidx) {
+		for (i=0; i<argc; i++)
+			sargv->targv[i] = argv[i];
+
+		sargv->cargv = slbt_default_cargv;
+
+		return 0;
+	}
+
 	/* split vectors: slibtool's own options */
 	for (i=0; i<ctx.unitidx; i++)
 		sargv->targv[i] = argv[i];
diff --git a/src/output/slbt_output_features.c b/src/output/slbt_output_features.c
new file mode 100644
index 0000000..b0252fa
--- /dev/null
+++ b/src/output/slbt_output_features.c
@@ -0,0 +1,40 @@
+/*******************************************************************/
+/*  slibtool: a skinny libtool implementation, written in C        */
+/*  Copyright (C) 2016--2017  Z. Gilboa                            */
+/*  Released under the Standard MIT License; see COPYING.SLIBTOOL. */
+/*******************************************************************/
+
+#include <stdio.h>
+#include <string.h>
+#include <stdbool.h>
+
+#include <slibtool/slibtool.h>
+#include "slibtool_errinfo_impl.h"
+
+static const char enable[]  = "enable";
+static const char disable[] = "disable";
+
+int slbt_output_features(const struct slbt_driver_ctx * dctx)
+{
+	const char * shared_option;
+	const char * static_option;
+
+	shared_option = (dctx->cctx->drvflags & SLBT_DRIVER_DISABLE_SHARED)
+		? disable : enable;
+
+	static_option = (dctx->cctx->drvflags & SLBT_DRIVER_DISABLE_STATIC)
+		? disable : enable;
+
+	if (fprintf(stdout,"host: %s\n",dctx->cctx->host.host) < 0)
+		return SLBT_SYSTEM_ERROR(dctx);
+
+	if (fprintf(stdout,"%s shared libraries\n",shared_option) < 0)
+		return SLBT_SYSTEM_ERROR(dctx);
+
+	if (fprintf(stdout,"%s static libraries\n",static_option) < 0)
+		return SLBT_SYSTEM_ERROR(dctx);
+
+	return fflush(stdout)
+		? SLBT_SYSTEM_ERROR(dctx)
+		: 0;
+}