[PATCH] prosproc.c: Fix building on musl libc

[Peter McGoron]

See ux.h for discussion about the interaction with musl and the
environ variable.
---
 src/microcode/prosproc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/microcode/prosproc.c b/src/microcode/prosproc.c
index ae5260906..704a16475 100644
--- a/src/microcode/prosproc.c
+++ b/src/microcode/prosproc.c
@@ -37,6 +37,7 @@ USA.
    #if !(defined(HAVE_DECL_ENVIRON) && HAVE_DECL_ENVIRON)
       #if defined(HAVE_DECL___ENVIRON) && HAVE_DECL___ENVIRON
          #define environ __environ
+      #elif defined(MUSL)
       #else
          extern char ** environ;
       #endif
-- 
2.52.0