Enable more compiler warnings. Some cleanup.

- cameo/Makefile (CFLAGS): added more warning flags
- cameo/path.h (path_direction): removed unused prototype
- cameo/path.c (angle): renamed to angle_3 to keep it from getting shadowed
  by local variable

cameo/Makefile

@@ -17,7 +17,9 @@ SHELL=/bin/bash
 MAIN=cameo
 OBJS=cameo.o gnuplot.o path.o
 
-CFLAGS=-Wall -g
+CFLAGS_WARN=-Wall -Wshadow -Wmissing-prototypes \
+            -Wmissing-declarations -Wno-format-zero-length
+CFLAGS=$(CFLAGS_WARN) -g
 LDFLAGS=-lm
 
 # ----- Verbosity control -----------------------------------------------------

cameo/path.c

@@ -162,7 +162,7 @@ static int left_turn(const struct point *a, const struct point *b,
  * in order to face towards C.
  */
 
-static double angle(const struct point *a, const struct point *b,
+static double angle_3(const struct point *a, const struct point *b,
     const struct point *c)
 {
 	double ax, ay, bx, by;
@@ -197,7 +197,7 @@ int path_tool_is_left(const struct path *path)
 	prev = path->first;
 	for (p = path->first->next; p; p = p->next) {
 		next = p->next ? p->next : path->first->next;
-		a += angle(prev, p, next);
+		a += angle_3(prev, p, next);
 		prev = p;
 	}
 	return a < 0;

cameo/path.h

@@ -30,7 +30,6 @@ struct path {
 struct path *path_new(double r_tool);
 void path_add(struct path *path, double x, double y, double z);
 struct path *path_reverse(const struct path *path);
-int path_direction(const struct path *path);
 int path_tool_is_left(const struct path *path);
 struct path *path_offset(const struct path *path, int left, int notch);
 void path_free(struct path *path);