fix: make function definitions visible for tests

src/cats/debug/debug_vital_rates.h

@@ -27,6 +27,7 @@
 #include "configuration/configuration.h"
 
 void debug_vital_rates(struct cats_configuration *conf, const struct program_options *command_line_options);
-
+struct cats_environment *minimal_suitability_environment(void);
+struct cats_grid *minimal_grid(struct cats_configuration *conf, struct cats_environment *env);
 
 #endif //CATS_DEBUG_VITAL_RATES_H