Fixing soname/install_name mac linking probs (#177)

  - When creating libnrnmech in mac the subsequent link would bring part of
    the original output dir into the link entry. That is because mac writes
    all outpyt libname in the install_name (similar to soname). Further, to
    be foundable via rpath, @rpath had to be in the name.
  - This patch fixes both issues and special-core now works in MAC
  - Fix lib soname in linux and _mod_func regen

Author: ferdonline

extra/nrnivmodl_core_makefile.in

@@ -24,6 +24,7 @@ datadir_mod2c := @CMAKE_INSTALL_PREFIX@/@CMAKE_INSTALL_DATADIR@/mod2c
 LDFLAGS = $(LINKFLAGS) @CORENRN_LINK_DEFS@
 CORENRNLIB_FLAGS = -L$(libdir) -lcoreneuron
 OS_NAME := $(shell uname)
+_cm =,
 
 # We rebuild the include dirs since a lot of stuff changes place
 INCLUDES = $(INCFLAGS) -I$(incdir) -I$(incdir)/coreneuron/utils/randoms
@@ -57,11 +58,12 @@ dimplic_o  = $(OBJS_DIR)/_dimplic.o
 
 special  = $(OUTPUT)/special-core
 LIB_SUFFIX_ = $(if $(MECH_NAME),_$(MECH_NAME),)
-coremech_libname = corenrnmech$(LIB_SUFFIX_)-$(MECH_VERSION)
+coremech_libname = corenrnmech$(LIB_SUFFIX_).$(MECH_VERSION)
 coremech_lib = $(OUTPUT)/lib$(coremech_libname)@CMAKE_SHARED_LIBRARY_SUFFIX@
 
 # If no DESTDIR (we are probably just building) we use $ORIGIN (@loader_path in OSX)
 _ORIGIN := $(if $(filter Darwin,$(OS_NAME)),@loader_path,$$ORIGIN)
+_SONAME := -Wl,$(if $(filter Darwin,$(OS_NAME)),-install_name${_cm}@rpath/,-soname${_cm})$(notdir ${coremech_lib})
 DESTDIR_RPATH = $(if $(DESTDIR),$(DESTDIR)/lib,$(_ORIGIN))
 
 C_RESET := \033[0m
@@ -78,9 +80,9 @@ $(special): $(coremech_lib)
 	  -L $(OUTPUT) -l$(coremech_libname) $(CORENRNLIB_FLAGS) -Wl,-rpath,'$(DESTDIR_RPATH)' -Wl,-rpath,$(libdir) $(LDFLAGS)
 
 
-$(coremech_lib): $(mod_func_o) $(dimplic_o) $(mod_objs)
+$(coremech_lib): $(mod_func_o) $(dimplic_o) $(mod_objs) build_always
 	@printf " => $(C_GREEN)LINKING$(C_RESET) library $(coremech_lib) Mod files: $(mod_files) (+ $(OPTMODS))\n"
-	$(CXX_LINK_SHARED) -I $(incdir) -DADDITIONAL_MECHS $(datadir)/enginemech.cpp -o ${coremech_lib} \
+	$(CXX_LINK_SHARED) -I $(incdir) -DADDITIONAL_MECHS $(datadir)/enginemech.cpp -o ${coremech_lib} ${_SONAME} \
 	  $(mod_func_o) $(dimplic_o) $(mod_objs) $(datadir)/libscopmath.a $(CORENRNLIB_FLAGS) -Wl,-rpath,$(libdir) $(LDFLAGS)
 
 
@@ -105,7 +107,7 @@ $(MODC_DIR)/%.cpp: $(datadir_mod2c)/%.cpp | $(MODC_DIR)
 $(mod_func_c): build_always | $(MODC_DIR)
 	@printf " -> $(C_GREEN)Generating$(C_RESET) $(mod_func_c)\n"
 	perl $(datadir)/mod_func.c.pl $(OPTMODS) $(mod_files) > $(mod_func_c).tmp
-	diff -q $(mod_func_c).tmp $(mod_func_c) || echo "Replacing mod_func.c" && mv $(mod_func_c).tmp $(mod_func_c)
+	diff -q $(mod_func_c).tmp $(mod_func_c) || { echo "Replacing mod_func.c"; mv $(mod_func_c).tmp $(mod_func_c); }
 
 
 # Header to avoid function callbacks using function pointers