glsl/apps: Assert that ftell does not return an error.

src/glsl/apps/compile.c

@@ -79,6 +79,7 @@ main(int argc,
 
    fseek(in, 0, SEEK_END);
    size = ftell(in);
+   assert(size != -1);
    fseek(in, 0, SEEK_SET);
 
    out = fopen(argv[3], "w");

src/glsl/apps/process.c

@@ -58,6 +58,7 @@ main(int argc,
 
    fseek(in, 0, SEEK_END);
    size = ftell(in);
+   assert(size != -1);
    fseek(in, 0, SEEK_SET);
 
    out = fopen(argv[2], "wb");

src/glsl/apps/purify.c

@@ -25,6 +25,7 @@
  * 
  **************************************************************************/
 
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -56,6 +57,7 @@ main(int argc,
 
    fseek(in, 0, SEEK_END);
    size = ftell(in);
+   assert(size != -1);
    fseek(in, 0, SEEK_SET);
 
    out = fopen(argv[2], "wb");

src/glsl/apps/tokenise.c

@@ -57,6 +57,7 @@ main(int argc,
 
    fseek(in, 0, SEEK_END);
    size = ftell(in);
+   assert(size != -1);
    fseek(in, 0, SEEK_SET);
 
    out = fopen(argv[2], "wb");

src/glsl/apps/version.c

@@ -56,6 +56,7 @@ main(int argc,
 
    fseek(in, 0, SEEK_END);
    size = ftell(in);
+   assert(size != -1);
    fseek(in, 0, SEEK_SET);
 
    out = fopen(argv[2], "wb");