BLD Make package build output less verbose (#947)

pyodide_build/buildall.py

@@ -72,10 +72,15 @@ class Package:
                     stderr=subprocess.STDOUT,
                 )
 
+        try:
+            p.check_returncode()
+        except subprocess.CalledProcessError:
+            print(f"Error building {self.name}. Printing build logs.")
+
             with open(self.pkgdir / "build.log", "r") as f:
                 shutil.copyfileobj(f, sys.stdout)
 
-        p.check_returncode()
+            raise
 
         if not self.library:
             shutil.copyfile(