[buildcore] Replace gmake < file with pybb cat

deps/buildcore/base.mk

@@ -48,7 +48,7 @@ ifneq ($(shell which docker 2> /dev/null),)
 		ENV_RUN=docker exec -i -t --user $(shell id -u ${USER}) ${DEVENV}
 	endif
 endif
-CURRENT_BUILD=$(HOST_ENV)-$(file < .current_build)
+CURRENT_BUILD=$(HOST_ENV)-$(shell ${PYBB} cat .current_build)
 
 .PHONY: build
 build:

deps/buildcore/scripts/pybb.py

@@ -17,10 +17,22 @@ import subprocess
 import sys
 
 
+def cat(path):
+    try:
+        with open(path) as f:
+            data = f.read()
+            print(data)
+        return 0
+    except FileNotFoundError:
+        sys.stderr.write('cat: {}: no such file or directory\n'.format(path))
+        return 1
+
+
 def mkdir(path):
     if not os.path.exists(path) and os.path.isdir(path):
         os.mkdir(path)
 
+
 # this exists because Windows is utterly incapable of providing a proper rm -rf
 def rm(path):
     if (os.path.exists(path) or os.path.islink(path)) and not os.path.isdir(path):
@@ -28,6 +40,7 @@ def rm(path):
     elif os.path.isdir(path):
         shutil.rmtree(path)
 
+
 def cmake_build(base_path, target):
     if not os.path.isdir(base_path):
         # nothing to build
@@ -40,6 +53,7 @@ def cmake_build(base_path, target):
         if err != 0:
             return err
 
+
 def main():
     if sys.argv[1] == 'mkdir':
         mkdir(sys.argv[2])
@@ -49,10 +63,13 @@ def main():
     elif sys.argv[1] == 'cmake-build':
         err = cmake_build(sys.argv[2], sys.argv[3] if len(sys.argv) > 3 else None)
         sys.exit(err)
+    elif sys.argv[1] == 'cat':
+        err = cat(sys.argv[2])
+        sys.exit(err)
+
 
 if __name__ == '__main__':
     try:
         main()
     except KeyboardInterrupt:
         sys.exit(1)
-