[syntacore] implemented basic embargo facilities

if we need to embargo the codebase, we'll need:

```
rm src/target/embargo/sc-ext/*
touch src/target/embargo/sc-ext/Makefile.am
```

Change-Id: I5f03a5a8f91dadd0004cea2414ab870358115fab

Author: aap-sc

configure.ac

@@ -402,6 +402,10 @@ AC_ARG_ENABLE([remote-bitbang],
   AS_HELP_STRING([--enable-remote-bitbang], [Enable building support for the Remote Bitbang driver]),
   [build_remote_bitbang=$enableval], [build_remote_bitbang=yes])
 
+AC_ARG_ENABLE([syntacore-extensions],
+  AS_HELP_STRING([--enable-syntacore-extensions], [Enable Syntacore extensions.]),
+  [syntacore_extensions=$enableval], [syntacore_extensions=no])
+
 AS_CASE(["${host_cpu}"],
   [i?86|x86*], [],
   [
@@ -645,6 +649,13 @@ AS_IF([test "x$enable_capstone" == xno], [
 	AC_DEFINE([HAVE_CAPSTONE], [0], [0 if you don't have Capstone disassembly framework.])
 ])
 
+AS_IF([test "x$enable_syntacore_extensions" = xyes], [
+		PKG_CHECK_MODULES([JANSSON], [jansson])
+		AC_DEFINE([SYNTACORE_EXTENSIONS],[1], [1 if SYNTACORE_EXTENSIONS support is included.])
+	], [
+		AC_DEFINE([SYNTACORE_EXTENSIONS],[0], [0 if SYNTACORE_EXTENSIONS support is excluded.])
+])
+
 for hidapi_lib in hidapi hidapi-hidraw hidapi-libusb; do
 	PKG_CHECK_MODULES([HIDAPI],[$hidapi_lib],[
 		use_hidapi=yes
@@ -764,6 +775,8 @@ AM_CONDITIONAL([RSHIM], [test "x$build_rshim" = "xyes"])
 AM_CONDITIONAL([DMEM], [test "x$build_dmem" = "xyes"])
 AM_CONDITIONAL([HAVE_CAPSTONE], [test "x$enable_capstone" != "xno"])
 
+AM_CONDITIONAL([SYNTACORE_EXTENSIONS], [test "x$enable_syntacore_extensions" = "xyes"])
+
 AM_CONDITIONAL([HAVE_JIMTCL_PKG_CONFIG], [test "x$have_jimtcl_pkg_config" = "xyes"])
 
 AM_CONDITIONAL([USE_GCOV], [test "x$enable_gcov" = "xyes"])

src/openocd.c

@@ -33,6 +33,10 @@
 #include <server/gdb_server.h>
 #include <server/rtt_server.h>
 
+#if SYNTACORE_EXTENSIONS
+#include <target/embargo/sc-ext/cmd.h>
+#endif
+
 #ifdef HAVE_STRINGS_H
 #include <strings.h>
 #endif
@@ -247,6 +251,9 @@ static int (* const command_registrants[])(struct command_context *cmd_ctx_value
 	cti_register_commands,
 	dap_register_commands,
 	arm_tpiu_swo_register_commands,
+#if SYNTACORE_EXTENSIONS
+	&syntacore_extensions_register_commands,
+#endif
 };
 
 static struct command_context *setup_command_handler(Jim_Interp *interp)
@@ -361,6 +368,9 @@ int openocd_main(int argc, char *argv[])
 	/* free all DAP and CTI objects */
 	arm_cti_cleanup_all();
 	dap_cleanup_all();
+#if SYNTACORE_EXTENSIONS
+	syntacore_extensions_cleanup();
+#endif
 
 	adapter_quit();
 

src/target/Makefile.am

@@ -242,3 +242,9 @@ include %D%/openrisc/Makefile.am
 include %D%/riscv/Makefile.am
 include %D%/xtensa/Makefile.am
 include %D%/espressif/Makefile.am
+
+if SYNTACORE_EXTENSIONS
+include %D%/embargo/sc-ext/Makefile.am
+%C%_libtarget_la_LIBADD += %D%/embargo/sc-ext/libscext.la
+endif
+