Only patch if file exists

Signed-off-by: Pedro Algarvio <palgarvio@vmware.com>

relenv/build/linux.py

@@ -3,6 +3,7 @@
 """
 The linux build process.
 """
+import pathlib
 import tempfile
 from .common import *
 from ..common import arches, LINUX
@@ -341,14 +342,18 @@ def build_python(env, dirs, logfp):
         ]
     )
 
-    with tempfile.NamedTemporaryFile(
-        node="w", suffix="_patch", delete_on_close=False
-    ) as patch_file:
-        patch_file.write(PATCH)
-        patch_file.close()
-        runcmd(
-            ["patch", "-p0", "-i", patch_file.name], env=env, stderr=logfp, stdout=logfp
-        )
+    if pathlib.Path("setup.py").exists():
+        with tempfile.NamedTemporaryFile(
+            node="w", suffix="_patch", delete_on_close=False
+        ) as patch_file:
+            patch_file.write(PATCH)
+            patch_file.close()
+            runcmd(
+                ["patch", "-p0", "-i", patch_file.name],
+                env=env,
+                stderr=logfp,
+                stdout=logfp,
+            )
 
     env["PKG_CONFIG_PATH"] = f"{dirs.prefix}/lib/pkgconfig"
     env["OPENSSL_CFLAGS"] = f"-I{dirs.prefix}/include  -Wno-coverage-mismatch"