Set module/*syspath* to JANET_PATH at build time

The takes out the hardcoded reference to /usr/local/

Makefile

@@ -35,7 +35,8 @@ MANPATH?=$(PREFIX)/share/man/man1/
 DEBUGGER=gdb
 
 CFLAGS=-std=c99 -Wall -Wextra -Isrc/include -fpic -O2 -fvisibility=hidden \
-	   -DJANET_BUILD=$(JANET_BUILD)
+	   -DJANET_BUILD=$(JANET_BUILD) \
+	   -DJANET_DEFAULT_PATH="\"$(JANET_PATH)\""
 
 UNAME:=$(shell uname -s)
 ifeq ($(UNAME), Darwin)

src/core/core.janet

@@ -1605,7 +1605,9 @@ value, one key will be ignored."
   and if that is not set /usr/local/lib/janet on linux/posix, and
   on Windows the default is the empty string."
   (or (os/getenv "JANET_PATH")
-      (if (= :windows (os/which)) "" "/usr/local/lib/janet")))
+      (if (= :windows (os/which)) "" JANET_DEFAULT_PATH)))
+
+(put _env 'JANET_DEFAULT_PATH nil)
 
 (defn- fexists [path]
   (def f (file/open path))

src/core/corelib.c

@@ -761,6 +761,8 @@ JanetTable *janet_core_env(void) {
 #endif
 
 #ifdef JANET_BOOTSTRAP
+    /* Let the bootstrap program know where to set the default path */
+    janet_core_def(env, "JANET_DEFAULT_PATH", janet_cstringv(JANET_DEFAULT_PATH), NULL);
     /* Run bootstrap source */
     janet_dobytes(env, janet_gen_core, janet_gen_core_size, "core.janet", NULL);
 #else