[source] perf: fix build with musl on PowerPC

[LEDE Commits]

neoraider pushed a commit to source.git, branch master:
https://git.lede-project.org/376944c0abe4c073faab17c450c3df1b0acda626

commit 376944c0abe4c073faab17c450c3df1b0acda626
Author: Matthias Schiffer <mschiffer at universe-factory.net>
AuthorDate: Wed Sep 28 06:14:09 2016 +0200

    perf: fix build with musl on PowerPC
    
    Signed-off-by: Matthias Schiffer <mschiffer at universe-factory.net>
---
 package/devel/perf/musl-include/asm/errno.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/package/devel/perf/musl-include/asm/errno.h b/package/devel/perf/musl-include/asm/errno.h
new file mode 100644
index 0000000..8c4b1be
--- /dev/null
+++ b/package/devel/perf/musl-include/asm/errno.h
@@ -0,0 +1,8 @@
+#ifndef __MUSL_COMPAT_ASM_ERRNO_H
+#define __MUSL_COMPAT_ASM_ERRNO_H
+
+/* Avoid including different versions of errno.h, the defines (incorrectly)
+ * cause a redefinition error on PowerPC */
+#include <errno.h>
+
+#endif