Further simplify the plugin installation process.

re: Unidata#2431

Hat tip to [DWesl](https://github.com/DWesl) and [opoplawski](https://github.com/opoplawski) for their help.

With some help, I found out how to get rid of the tmp_LTLIBARIES
hack and replace it with check_LTLIBRARIES.

Using check_LTLIBRARIES means also that the test libraries are not
built until "make check" is executed.

This PR replaces the one above.

nc_test4/findplugin.in

@@ -37,10 +37,8 @@ findpluginext() {
   TDY=`find ${TOPBUILDDIR}/plugins -name '*misc.dylib'`
   TCYG=`find ${TOPBUILDDIR}/plugins -name 'cyg*misc.dll'`
   TDLL=`find ${TOPBUILDDIR}/plugins -name '*misc.dll'`
-  if test "x$TSO" != x ; then
-    FP_PLUGIN_EXT="so"
-    FP_PLUGIN_PRE="lib__nc"  
-  elif test "x$TDY" != x ; then
+  # Test order may be important esp for dylib vs so
+  if test "x$TDY" != x ; then
     FP_PLUGIN_EXT="dylib"
     FP_PLUGIN_PRE="lib__nc"  
   elif test "x$TCYG" != x ; then
@@ -49,6 +47,9 @@ findpluginext() {
   elif test "x$TDLL" != x ; then
     FP_PLUGIN_EXT="dll"
     FP_PLUGIN_PRE="__nc"  
+  elif test "x$TSO" != x ; then
+    FP_PLUGIN_EXT="so"
+    FP_PLUGIN_PRE="lib__nc"  
   else # unknown
     unset FP_PLUGIN_EXT
     unset FP_PLUGIN_PRE

nc_test4/tst_unknown.sh

@@ -53,8 +53,6 @@ UNKNOWNDIR="${HDF5_PLUGIN_DIR}"
 UNKNOWNLIB="${HDF5_PLUGIN_LIB}"
 UNKNOWNFILTER="${HDF5_PLUGIN_DIR}/${UNKNOWNLIB}"
 
-# Getting the name  is especially tricky for dylib, which puts the version before the .dylib
-
 # Verify
 if ! test -f ${UNKNOWNFILTER} ; then echo "Unable to locate ${UNKNOWNFILTER}"; exit 1; fi
 

nc_test4/tst_vars3.c

@@ -418,7 +418,7 @@ main(int argc, char **argv)
         if (nc_close(ncid)) ERR;
     }
     SUMMARIZE_ERR;
-#ifdef HAVE_SZ
+#ifdef HAVE_H5Z_SZIP
     printf("**** testing simple szip filter setup...");
     {
         int ncid;
@@ -748,9 +748,9 @@ main(int argc, char **argv)
         params[1] = NC_SZIP_EC_BPP_IN; /* pixels_per_block */
         if (nc_def_var_chunking(ncid, varid, NC_CHUNKED, NULL)) ERR;
         { int stat;
-	  if ((stat = nc_def_var_filter(ncid, varid, H5_FILTER_SZIP, NUM_PARAMS_IN,
-            params)) != NC_ENOFILTER)
-            ERR;
+	  stat = nc_def_var_filter(ncid, varid, H5_FILTER_SZIP, NUM_PARAMS_IN, params);
+	  if(stat != NC_ENOFILTER) 
+              ERR;
         }
         if (nc_def_var_szip(ncid, varid, NC_SZIP_NN,
                             NC_SZIP_EC_BPP_IN) != NC_ENOFILTER) ERR;

plugins/Makefile.am

@@ -4,31 +4,28 @@
 # Put Together AM_CPPFLAGS and AM_LDFLAGS
 include $(top_srcdir)/lib_flags.am
 
-AM_LDFLAGS += -module -avoid-version -shared -export-dynamic	\
- -rpath ${abs_builddir} ${NOUNDEFINED}
-
-# Create an alternate directory if not installing or for noinst installs.
-ALTPLUGINDIR = ${abs_top_builddir}/plugins/plugindir
-
-# This is where the plugins are to be installed
-if ENABLE_PLUGIN_DIR
+#if ENABLE_PLUGIN_DIR
 plugindir = @PLUGIN_INSTALL_DIR@
-else
-plugindir = ${ALTPLUGINDIR}
-endif
+#else
+plugindir = ${prefix}
+#endif
 
-plugin_LTLIBRARIES =
+AM_LDFLAGS += -module -avoid-version -shared -export-dynamic ${NOUNDEFINED} 
+
+# There seems no guaranteed way to turn of the version in the name
+#plugin_version_info = -no-version-info 0:0:0
 
-# Apparently one cannot have plugin_LTLIBRARIES and also noinst_LTLIBRARIES.
-# So create a tmp location for "noinst" shared libraries.
-tmpdir = ${ALTPLUGINDIR}
+# Use this only with installable libraries
+# Not currently needed for the platforms we support.
+#INSTALLFLAGS = -rpath ${plugindir} ${plugin_version_info}
 
-tmp_LTLIBRARIES =
+# Use this only with test libraries
+# Note: it appears necessary to set rpath for the check libraries
+# so that they get generated
+TESTFLAGS = -rpath ${plugindir}
 
-# This linker flag specifies libtool version info.
-# See http://www.gnu.org/software/libtool/manual/libtool.html#Libtool-versioning
-# for information regarding incrementing `-version-info`.
-plugin_version_info = -version-info 0:0:0
+plugin_LTLIBRARIES =
+check_LTLIBRARIES =
 
 if ISMINGW
 LDADD =  ${top_builddir}/liblib/libnetcdf.la
@@ -52,18 +49,19 @@ if ENABLE_FILTER_TESTING
 if ENABLE_NCZARR_FILTERS
 plugin_LTLIBRARIES += lib__nch5fletcher32.la lib__nch5shuffle.la lib__nch5deflate.la
 lib__nch5shuffle_la_SOURCES = H5Zshuffle.c
+lib__nch5shuffle_la_LDFLAGS = ${INSTALLFLAGS}
 lib__nch5fletcher32_la_SOURCES = H5Zfletcher32.c H5checksum.c
+lib__nch5fletcher32_la_LDFLAGS = ${INSTALLFLAGS}
 lib__nch5deflate_la_SOURCES = H5Zdeflate.c
+lib__nch5deflate_la_LDFLAGS = ${INSTALLFLAGS}
 
-lib__nch5shuffle_la_LDFLAGS = ${plugin_version_info}
-lib__nch5deflate_la_LDFLAGS = ${plugin_version_info}
-lib__nch5fletcher32_la_LDFLAGS = ${plugin_version_info}
-
-# Need our version of szip if libsz available and we are not using HDF5
+# Need our version of szip if libsz available and we are using nczarr
 if HAVE_SZ
+if ENABLE_NCZARR_FILTERS
 plugin_LTLIBRARIES += lib__nch5szip.la
 lib__nch5szip_la_SOURCES = H5Zszip.c H5Zszip.h
-lib__nch5szip_la_LDFLAGS = ${plugin_version_info}
+lib__nch5szip_la_LDFLAGS = ${INSTALLFLAGS}
+endif
 endif
 
 endif # ENABLE_NCZARR_FILTERS
@@ -72,20 +70,21 @@ if ENABLE_PLUGINS
 
 # The NCZarr codec libraries
 lib__nczstdfilters_la_SOURCES = NCZstdfilters.c
+lib__nczstdfilters_la_LDFLAGS = ${INSTALLFLAGS}
 lib__nczhdf5filters_la_SOURCES = NCZhdf5filters.c
-
+lib__nczhdf5filters_la_LDFLAGS = ${INSTALLFLAGS}
 plugin_LTLIBRARIES += lib__nczhdf5filters.la
 plugin_LTLIBRARIES += lib__nczstdfilters.la
 
 if HAVE_BLOSC
 lib__nch5blosc_la_SOURCES = H5Zblosc.c H5Zblosc.h
-lib__nch5blosc_la_LDFLAGS = ${plugin_version_info}
+lib__nch5blosc_la_LDFLAGS = ${INSTALLFLAGS}
 plugin_LTLIBRARIES += lib__nch5blosc.la
 endif
 
 if HAVE_ZSTD
 lib__nch5zstd_la_SOURCES = H5Zzstd.c H5Zzstd.h
-lib__nch5zstd_la_LDFLAGS = ${plugin_version_info}
+lib__nch5zstd_la_LDFLAGS = ${INSTALLFLAGS}
 plugin_LTLIBRARIES += lib__nch5zstd.la
 endif
 
@@ -95,20 +94,20 @@ endif #ENABLE_PLUGINS
 # Need two distinct instances
 lib__nch5noop_la_SOURCES = H5Znoop.c H5Zutil.c h5noop.h
 lib__nch5noop1_la_SOURCES = H5Znoop1.c H5Zutil.c h5noop.h
-lib__nch5noop_la_LDFLAGS = ${plugin_version_info}
-lib__nch5noop1_la_LDFLAGS = ${plugin_version_info}
+lib__nch5noop_la_LDFLAGS = ${TESTFLAGS}
+lib__nch5noop1_la_LDFLAGS = ${TESTFLAGS}
 
 # The misc filter is to allow testing of filter arguments
 lib__nch5misc_la_SOURCES = H5Zmisc.c H5Zutil.c h5misc.h
-lib__nch5misc_la_LDFLAGS = ${plugin_version_info}
+lib__nch5misc_la_LDFLAGS = ${TESTFLAGS}
 lib__nczmisc_la_SOURCES = NCZmisc.c
-lib__nczmisc_la_LDFLAGS = ${plugin_version_info}
+lib__nczmisc_la_LDFLAGS = ${TESTFLAGS}
 
 # Provide a filter to test missing filter
 lib__nch5unknown_la_SOURCES = H5Zunknown.c
-lib__nch5unknown_la_LDFLAGS = ${plugin_version_info}
+lib__nch5unknown_la_LDFLAGS = ${TESTFLAGS}
 
-tmp_LTLIBRARIES += lib__nch5noop.la lib__nch5noop1.la lib__nch5misc.la lib__nczmisc.la lib__nch5unknown.la
+check_LTLIBRARIES += lib__nch5noop.la lib__nch5noop1.la lib__nch5misc.la lib__nczmisc.la lib__nch5unknown.la
 
 # Bzip2 is used to test more complex filters
 lib__nch5bzip2_la_SOURCES = H5Zbzip2.c h5bzip2.h
@@ -117,7 +116,7 @@ EXTRA_DIST += ${BZIP2SRC} BZIP2_LICENSE
 if HAVE_LOCAL_BZ2
 lib__nch5bzip2_la_SOURCES += ${BZIP2SRC}
 endif
-lib__nch5bzip2_la_LDFLAGS = ${plugin_version_info}
+lib__nch5bzip2_la_LDFLAGS = ${INSTALLFLAGS}
 plugin_LTLIBRARIES += lib__nch5bzip2.la
 
 endif #ENABLE_FILTER_TESTING
@@ -138,8 +137,3 @@ bzip2::
 	tar -zxf ${BZIP2DIR}.tar.gz
 	cd ${BZIP2DIR}; cp ${BZIP2SRC} ..; cp LICENSE ../BZIP2_LICENSE ; cd ..
 	rm -fr ./${BZIP2DIR}
-
-# Custom clean
-clean-local:
-	rm -fr ${ALTPLUGINDIR}
-

test_common.in

@@ -5,6 +5,10 @@
 
 # See netcdf-c/COPYRIGHT file for more info.
 
+# Call only once per shell script
+if test "x$TEST_COMMON_INITIALIZE" != xyes ; then
+TEST_COMMON_INITIALIZE=yes
+
 # Define location of execution
 TOPSRCDIR='@abs_top_srcdir@'
 TOPBUILDDIR='@abs_top_builddir@'
@@ -172,3 +176,6 @@ if test yes = `${execdir}/../ncdump/ncfilteravail $1` ; then return 0 ; else ech
 
 # Make sure we are in builddir (not execdir)
 cd $builddir
+
+fi # TTEST_COMMON_INITIALIZE
+