[ISSUE-10] Implemented propagation of pg sphere version.

Makefile

@@ -32,6 +32,9 @@ TESTS       = init_test tables points euler circle line ellipse poly path box in
 			  contains_ops contains_ops_compat bounding_box_gist gnomo healpix \
 			  moc mocautocast epochprop
 
+PG_CFLAGS	+= -DPGSPHERE_VERSION=$(PGSPHERE_VERSION)
+PG_CPPFLAGS	+= -DPGSPHERE_VERSION=$(PGSPHERE_VERSION)
+
 ifndef CXXFLAGS
 # no support for CXXFLAGS in PGXS before v11
 CXXFLAGS = -Wall -Wpointer-arith -Wendif-labels \

expected/init.out

@@ -3,3 +3,9 @@
 -- does not depend on contents of pg_sphere.sql.
 --
 CREATE EXTENSION pg_sphere;
+select pg_sphere_version();
+ pg_sphere_version 
+-------------------
+ 1.2.1
+(1 row)
+

sql/init.sql

@@ -3,3 +3,5 @@
 -- does not depend on contents of pg_sphere.sql.
 --
 CREATE EXTENSION pg_sphere;
+
+select pg_sphere_version();

src/output.c

@@ -1,5 +1,12 @@
 #include "types.h"
 
+#if !defined(PGSPHERE_VERSION)
+#error "PGSPHERE_VERSION macro is not set"
+#endif
+
+#define PGSPHERE_STRINGIFY_INTERNAL(x) #x
+#define PGSPHERE_STRINGIFY(x) PGSPHERE_STRINGIFY_INTERNAL(x)
+
 /* Output functions */
 
 
@@ -527,7 +534,8 @@ spherebox_out(PG_FUNCTION_ARGS)
 Datum
 pg_sphere_version(PG_FUNCTION_ARGS)
 {
-	char	   *buffer = (char *) palloc(20);
-	sprintf(buffer, "1.1.5");
-	PG_RETURN_CSTRING(buffer);
+	const char	*s = PGSPHERE_STRINGIFY(PGSPHERE_VERSION);
+	char		*p = (char *)palloc(strlen(s) + 1);
+	strcpy(p, s);
+	PG_RETURN_CSTRING(p);
 }