Introduced recipe repositories.

SConscript

@@ -55,8 +55,14 @@ def _find_recipe(env: Environment, recipe_name: str):
         return env['SPP_RECIPES'][recipe_name]
     import importlib.util
     source_file = None
-    for folder in env['RECIPES_FOLDERS']:
-        try_source_file = f'{folder.abspath}/{recipe_name}/recipe.py'
+
+    if not env['SPP_RECIPES_FOLDERS']:
+        env.Error('No recipes repositories set. Add one using env.RecipeRepo(<name>, <url>, <branch>).')
+    for folder in env['SPP_RECIPES_FOLDERS']:
+        from SCons import Node
+        if folder is Node:
+            folder = folder.abspath
+        try_source_file = f'{folder}/{recipe_name}/recipe.py'
         if os.path.exists(try_source_file):
             source_file = try_source_file
             break
@@ -767,7 +773,7 @@ if 'TOOLS' in config:
     tools.extend(config['TOOLS'])
 
 env = Environment(tools = tools, variables = vars, ENV = os.environ)
-env['RECIPES_FOLDERS'] = [Dir('recipes')]
+env['SPP_RECIPES_FOLDERS'] = []
 env['SYSTEM_CACHE_DIR'] = os.path.join(_find_system_cache_dir(), 'spp_cache')
 env['CLONE_DIR'] = os.path.join(env['SYSTEM_CACHE_DIR'], 'cloned')
 env['DOWNLOAD_DIR'] = os.path.join(env['SYSTEM_CACHE_DIR'], 'downloaded')
@@ -889,7 +895,7 @@ elif unity_mode == 'stress': # compile everything in one single file to stress t
 
 # setup compiler specific options
 if env['COMPILER_FAMILY'] == 'gcc' or env['COMPILER_FAMILY'] == 'clang':
-    env.Append(CCFLAGS = ['-Wall', '-Wextra', '-Werror', '-Wstrict-aliasing', '-pedantic'])
+    env.Append(CCFLAGS = ['-Wall', '-Wextra', '-Werror', '-Wstrict-aliasing', '-pedantic', '-fvisibility=hidden'])
     env.Append(CXXFLAGS = [f'-std={config["CXX_STANDARD"]}'])
     if env['CXX_NO_EXCEPTIONS']:
         env.Append(CXXFLAGS = [f'-fno-exceptions'])