From b7df39cc12e77c05f54a0257f4b355ea808f5408 Mon Sep 17 00:00:00 2001
From: Bryan Drewery <bdrewery@FreeBSD.org>
Date: Tue, 8 Dec 2015 20:20:40 +0000
Subject: [PATCH] CCACHE_BUILD: Only export CCACHE_PATH= if it was already set
 with a value.

Older ccache don't work with an empty CCACHE_PATH value.  They will error with:
  ccache: FATAL: Could not find compiler "cc" in PATH
  make: "/mnt/bdrewery/git/onefs/src/share/mk/bsd.compiler.mk" line 134: Unable to determine compiler type for /usr/local/bin/ccache cc.  Consider setting COMPILER_TYPE.

Sponsored by:	EMC / Isilon Storage Division
---
 share/mk/bsd.compiler.mk | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/share/mk/bsd.compiler.mk b/share/mk/bsd.compiler.mk
index e5d349adf738..d7763e4e06b4 100644
--- a/share/mk/bsd.compiler.mk
+++ b/share/mk/bsd.compiler.mk
@@ -64,8 +64,10 @@ CCACHE_COMPILERCHECK?=	mtime
 # Remove ccache from the PATH to prevent double calls and wasted CPP/LD time.
 PATH:=	${PATH:C,:?${CCACHE_WRAPPER_PATH}(/world)?(:$)?,,g}
 # Ensure no bogus CCACHE_PATH leaks in which might avoid the in-tree compiler.
+.if !empty(CCACHE_PATH)
 CCACHE_PATH=
 .export CCACHE_PATH
+.endif
 # Override various toolchain vars.
 .for var in CC CXX HOST_CC HOST_CXX
 .if defined(${var}) && ${${var}:M${CCACHE_BIN}} == ""