Improve compiler detection

So far compilers needed to be specified twice (as usual with Travis
in "compiler" as well as in our own CMPLR environment variable).
This change allows our scripts to use the compiler specified with
Travis (no need to populate CMPLR anymore).

.travis.yml.example-full

@@ -34,12 +34,12 @@ matrix:
 
   - env: BRBASE=7.0
 
-  - env: BRBASE=7.0 CMPLR=clang
+  - env: BRBASE=7.0
     compiler: clang
 
   - env: BRBASE=7.0 EXTRA="CMD_CXXFLAGS=-std=c++11"
 
-  - env: BRBASE=7.0 CMPLR=clang EXTRA="CMD_CXXFLAGS=-std=c++11"
+  - env: BRBASE=7.0 EXTRA="CMD_CXXFLAGS=-std=c++11"
     compiler: clang
 
 # Cross-compilation to Windows using MinGW and WINE
@@ -58,12 +58,12 @@ matrix:
 
 # Other gcc versions (adding as an extra package)
 
-  - env: BRBASE=7.0 CMPLR=gcc-6
+  - env: BRBASE=7.0
     dist: xenial
 	compiler: gcc-6
 	addons: { apt: { packages: ["g++-6"], sources: ["ubuntu-toolchain-r-test"] } }
 
-  - env: BRBASE=7.0 CMPLR=gcc-7
+  - env: BRBASE=7.0
     dist: xenial
 	compiler: gcc-7
 	addons: { apt: { packages: ["g++-7"], sources: ["ubuntu-toolchain-r-test"] } }

travis-prepare.sh

@@ -63,38 +63,35 @@ STATIC_BUILD=YES
 EOF
 fi
 
-case "$CMPLR" in
+HOST_CCMPLR_NAME=`echo "$TRAVIS_COMPILER" | sed -E 's/^([[:alpha:]][^-]*(-[[:alpha:]][^-]*)*)+(-[0-9\.]+)?$/\1/g'`
+HOST_CMPLR_VER_SUFFIX=`echo "$TRAVIS_COMPILER" | sed -E 's/^([[:alpha:]][^-]*(-[[:alpha:]][^-]*)*)+(-[0-9\.]+)?$/\3/g'`
+HOST_CMPLR_VER=`echo "$HOST_CMPLR_VER_SUFFIX" | cut -c 2-`
+
+case "$HOST_CCMPLR_NAME" in
 clang)
   echo "Host compiler is clang"
+  HOST_CPPCMPLR_NAME=$(echo "$HOST_CCMPLR_NAME" | sed 's/clang/clang++/g')
   cat << EOF >> epics-base/configure/os/CONFIG_SITE.Common.$EPICS_HOST_ARCH
 GNU         = NO
 CMPLR_CLASS = clang
-CC          = clang
-CCC         = clang++
+CC          = ${HOST_CCMPLR_NAME}$HOST_CMPLR_VER_SUFFIX
+CCC         = ${HOST_CPPCMPLR_NAME}$HOST_CMPLR_VER_SUFFIX
 EOF
 
   # hack
   sed -i -e 's/CMPLR_CLASS = gcc/CMPLR_CLASS = clang/' epics-base/configure/CONFIG.gnuCommon
 
-  clang --version
+  ${HOST_CCMPLR_NAME}$HOST_CMPLR_VER_SUFFIX --version
   ;;
-gcc-6)
-  echo "Host compiler is gcc-6"
+gcc)
+  echo "Host compiler is GCC"
+  HOST_CPPCMPLR_NAME=$(echo "$HOST_CCMPLR_NAME" | sed 's/gcc/g++/g')
   cat << EOF >> epics-base/configure/os/CONFIG_SITE.Common.$EPICS_HOST_ARCH
-CC          = gcc-6
-CCC         = g++-6
+CC          = ${HOST_CCMPLR_NAME}$HOST_CMPLR_VER_SUFFIX
+CCC         = ${HOST_CPPCMPLR_NAME}$HOST_CMPLR_VER_SUFFIX
 EOF
 
-  gcc-6 --version
-  ;;
-gcc-7)
-  echo "Host compiler is gcc-7"
-  cat << EOF >> epics-base/configure/os/CONFIG_SITE.Common.$EPICS_HOST_ARCH
-CC          = gcc-7
-CCC         = g++-7
-EOF
-
-  gcc-7 --version
+  ${HOST_CCMPLR_NAME}$HOST_CMPLR_VER_SUFFIX --version
   ;;
 *)
   echo "Host compiler is default"