diff --git a/Makefile b/Makefile
index 82d992d..2559ad9 100644
--- a/Makefile
+++ b/Makefile
@@ -15,7 +15,7 @@ EXTRA_CLEAN = y.tab.c y.tab.h \
 				jsquery_gram.c jsquery_scan.c jsquery_gram.h
 
 ifdef USE_PGXS
-PG_CONFIG = pg_config
+PG_CONFIG ?= pg_config
 PGXS := $(shell $(PG_CONFIG) --pgxs)
 include $(PGXS)
 else
diff --git a/README.md b/README.md
index 21ecddf..0fae891 100644
--- a/README.md
+++ b/README.md
@@ -49,7 +49,7 @@ Before build and install you should ensure following:
    PostgreSQL from source.
  * You have flex and bison installed on your system. JsQuery was tested on
    flex 2.5.37-2.5.39, bison 2.7.12.
- * Your PATH variable is configured so that pg\_config command available.
+ * Your PATH variable is configured so that pg\_config command available, or set PG_CONFIG variable.
     
 Typical installation procedure may look like this: