Remove the NANOPB_INTERNALS functions from public API.

These have been deprecated since nanopb-0.1.6 (some since 0.1.3).
Equivalent functions with better interface are available in the API.

Update issue 91
Status: FixedInGit

tests/SConstruct

@@ -78,6 +78,8 @@ if 'gcc' in env['CC']:
 
     # More strict checks on the nanopb core
     env.Append(CORECFLAGS = '-Wextra -Wcast-qual -Wlogical-op -Wconversion')
+    env.Append(CORECFLAGS = ' -Wmissing-prototypes -Wmissing-declarations -Wredundant-decls')
+    env.Append(CORECFLAGS = ' -Wstack-protector')
 elif 'clang' in env['CC']:
     # CLang
     env.Append(CFLAGS = '-ansi -g -O0 -Wall -Werror')