gitian: omit ccache from gitian builds

It's just wasted overhead since the build VMs are always deleted
and recreated fresh for each run.

contrib/depends/packages/packages.mk

@@ -1,6 +1,9 @@
 packages:=boost openssl zeromq libiconv
 
+# ccache is useless in gitian builds
+ifneq ($(GITIAN),1)
 native_packages := native_ccache
+endif
 
 hardware_packages := hidapi protobuf libusb
 hardware_native_packages := native_protobuf

contrib/gitian/gitian-android.yml

@@ -24,7 +24,6 @@ packages:
 - "ca-certificates"
 - "python"
 - "cmake"
-- "ccache"
 - "protobuf-compiler"
 - "libdbus-1-dev"
 - "libharfbuzz-dev"
@@ -52,6 +51,7 @@ script: |
   if test -n "$GBUILD_CACHE_ENABLED"; then
     export SOURCES_PATH=${GBUILD_COMMON_CACHE}
     export BASE_CACHE=${GBUILD_PACKAGE_CACHE}
+    export GITIAN=1
     mkdir -p ${BASE_CACHE} ${SOURCES_PATH}
   fi
 

contrib/gitian/gitian-freebsd.yml

@@ -25,7 +25,6 @@ packages:
 - "ca-certificates"
 - "python"
 - "cmake"
-- "ccache"
 - "protobuf-compiler"
 - "libdbus-1-dev"
 - "libharfbuzz-dev"
@@ -52,6 +51,7 @@ script: |
   if test -n "$GBUILD_CACHE_ENABLED"; then
     export SOURCES_PATH=${GBUILD_COMMON_CACHE}
     export BASE_CACHE=${GBUILD_PACKAGE_CACHE}
+    export GITIAN=1
     mkdir -p ${BASE_CACHE} ${SOURCES_PATH}
   fi
 

contrib/gitian/gitian-linux.yml

@@ -36,7 +36,6 @@ packages:
 - "ca-certificates"
 - "python"
 - "cmake"
-- "ccache"
 - "protobuf-compiler"
 - "libdbus-1-dev"
 - "libharfbuzz-dev"
@@ -63,6 +62,7 @@ script: |
   if test -n "$GBUILD_CACHE_ENABLED"; then
     export SOURCES_PATH=${GBUILD_COMMON_CACHE}
     export BASE_CACHE=${GBUILD_PACKAGE_CACHE}
+    export GITIAN=1
     mkdir -p ${BASE_CACHE} ${SOURCES_PATH}
   fi
 

contrib/gitian/gitian-osx.yml

@@ -41,6 +41,7 @@ script: |
   if test -n "$GBUILD_CACHE_ENABLED"; then
     export SOURCES_PATH=${GBUILD_COMMON_CACHE}
     export BASE_CACHE=${GBUILD_PACKAGE_CACHE}
+    export GITIAN=1
     mkdir -p ${BASE_CACHE} ${SOURCES_PATH}
   fi
 

contrib/gitian/gitian-win.yml

@@ -54,6 +54,7 @@ script: |
   if test -n "$GBUILD_CACHE_ENABLED"; then
     export SOURCES_PATH=${GBUILD_COMMON_CACHE}
     export BASE_CACHE=${GBUILD_PACKAGE_CACHE}
+    export GITIAN=1
     mkdir -p ${BASE_CACHE} ${SOURCES_PATH}
   fi