build: Make ccache opt-in rather than opt-out

Using ccache by default for compilation if it is available on the system
might confuse people and in rare cases also lead to unexpected results.
Thus, from now on the use of ccache for compilation has to explicitely
specified by setting the CCACHE make variable to the name/path of the
ccache binary, i.e. `make CCACHE=ccache'

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

3 files changed, 4 insertions, 18 deletions

diff --git a/Makefile b/Makefile
index f76fa10..968f9b7 100644
--- a/Makefile
+++ b/Makefile
@@ -25,8 +25,8 @@ TOOLS ?= netsniff-ng trafgen astraceroute flowtop ifpps bpfc curvetun mausezahn
 # For packaging purposes, prefix can define a different path.
 PREFIX ?= /usr/local
 
-# Disable if you don't want it
-CCACHE ?= $(CONFIG_CCACHE)
+# Set to use ccache for compilation
+CCACHE ?=
 
 # Location of an alternative destination directory for installation
 # Useful when cross-compiling and installing in a dedicated target directory
diff --git a/Misc b/Misc
index 4639280..818c4a3 100644
--- a/Misc
+++ b/Misc
@@ -67,7 +67,7 @@ coverity:
 	$(Q)$(call RM,cov-int)
 	$(Q)$(call MKDIR,cov-int)
 	$(Q)./configure
-	$(Q)cov-build --dir cov-int $(MAKE) CCACHE=
+	$(Q)cov-build --dir cov-int $(MAKE)
 	$(Q)tar czvf netsniff-ng-coverity.tgz cov-int
 	$(Q)echo "Uploading snapshot to Coverity scanner"
 	$(Q)curl --form file=@netsniff-ng-coverity.tgz --form project=netsniff-ng \
@@ -113,6 +113,6 @@ help:
 	$(Q)echo " CFLAGS=\"-O2 -Wall ...\"       - Overwrite CFLAGS for compilation"
 	$(Q)echo " CPPFLAGS=\"-I <path> ...\"     - Additional CFLAGS for compilation"
 	$(Q)echo " LDFLAGS=\"-L <path> ...\"      - Additional LDFLAGS for compilation"
-	$(Q)echo " CCACHE=                      - Do not use ccache for compilation"
+	$(Q)echo " CCACHE=ccache                - Use ccache for compilation"
 	$(Q)echo " C=1                          - Check all C source files with sparse"
 	$(Q)echo " Q=                           - Show verbose garbage"
diff --git a/configure b/configure
index fa60764..2e553cb 100755
--- a/configure
+++ b/configure
@@ -55,19 +55,6 @@ check_pkg_config()
 	fi
 }
 
-check_ccache()
-{
-	echo -n "[*] Checking ccache ... "
-
-	if [ "x$(which ccache 2>> config.log)" == "x" ] ; then
-		echo "[NO]"
-		echo "CONFIG_CCACHE=" >> Config
-	else
-		echo "[YES]"
-		echo "CONFIG_CCACHE=ccache" >> Config
-	fi
-}
-
 check_flex()
 {
 	echo -n "[*] Checking flex ... "
@@ -590,7 +577,6 @@ if [ "$MISSING_PKG_CONFIG" == "1" ] ; then
 	exit 1
 fi
 
-check_ccache
 check_flex
 check_bison
 check_nacl