Makefile: enable symbol versioning by default

This enables symbol versioning by default, with the version string
`JL_LIBJULIA_1.10` (the version suffix is the SOMAJOR in general).

As part of this change, the SOMAJOR has also been changed to be
MAJOR.MINOR instead of just MAJOR. This is required to allow multiple
minor releases of libjulia to live side-by-side in the same process.

`SYMBOL_VERSION_SUFFIX` is provided to allow appending an additional
unique "salt" to SOMAJOR, which can be helpful for creating template
binaries that will be "version-stamped" after distribution.

Make.inc

@@ -188,21 +188,17 @@ JULIA_MINOR_VERSION := $(shell echo $(JULIA_VERSION) | cut -d'-' -f 1 | cut -d'.
 JULIA_PATCH_VERSION := $(shell echo $(JULIA_VERSION) | cut -d'-' -f 1 | cut -d'+' -f 1 | cut -d'.' -f 3)
 
 # libjulia's SONAME will follow the format libjulia.so.$(SOMAJOR). Before v1.0.0,
-# SOMAJOR will be a two-decimal value, e.g. libjulia.so.0.5, whereas at and beyond
-# v1.0.0, SOMAJOR will be simply the major version number, e.g. libjulia.so.1
+# somajor was a two-decimal value (e.g. libjulia.so.0.5). During v1.0.x - v1.9.x,
+# somajor was simply the major version number (e.g. libjulia.so.1). Starting in
+# v1.10.0, somajor is major.minor again (e.g. libjulia.so.1.10)
 # The file itself will ultimately symlink to libjulia.so.$(SOMAJOR).$(SOMINOR)
-ifeq ($(JULIA_MAJOR_VERSION),0)
 SOMAJOR := $(JULIA_MAJOR_VERSION).$(JULIA_MINOR_VERSION)
 SOMINOR := $(JULIA_PATCH_VERSION)
-else
-SOMAJOR := $(JULIA_MAJOR_VERSION)
-SOMINOR := $(JULIA_MINOR_VERSION)
-endif
 
-# In order to load multiple libjulia's with different DEFAULT_SYMBOL_VERSION
-# each must have a unique SONAME
-ifdef DEFAULT_SYMBOL_VERSION
-SOMAJOR := "$(SOMAJOR)-$(DEFAULT_SYMBOL_VERSION)"
+# This suffix affects libjulia's SONAME and the symbol version associated with
+# all of its exported symbols.
+ifdef SYMBOL_VERSION_SUFFIX
+SOMAJOR := $(SOMAJOR)_$(SYMBOL_VERSION_SUFFIX)
 endif
 
 ifneq ($(NO_GIT), 1)

cli/Makefile

@@ -149,7 +149,7 @@ $(build_bindir)/julia-debug$(EXE): $(EXE_DOBJS) $(build_shlibdir)/libjulia-debug
 	@$(call PRINT_LINK, $(CC) $(LOADER_CFLAGS) $(DEBUGFLAGS) $(EXE_DOBJS) -o $@ $(LOADER_LDFLAGS) $(RPATH) -ljulia-debug)
 
 $(BUILDDIR)/julia.expmap: $(SRCDIR)/julia.expmap.in
-	sed <'$<' >'$@' -e 's/@JULIA_SHLIB_SYMBOL_VERSION@/$(DEFAULT_SYMBOL_VERSION)/'
+	sed <'$<' >'$@' -e 's/@JULIA_SHLIB_SYMBOL_VERSION@/JL_LIBJULIA_$(SOMAJOR)/'
 
 clean: | $(CLEAN_TARGETS)
 	rm -f $(BUILDDIR)/*.o $(BUILDDIR)/*.dbg.obj

src/Makefile

@@ -366,7 +366,7 @@ $(BUILDDIR)/julia_version.h: $(JULIAHOME)/VERSION
 CXXLD = $(CXX) -shared
 
 $(BUILDDIR)/julia.expmap: $(SRCDIR)/julia.expmap.in
-	sed <'$<' >'$@' -e 's/@JULIA_SHLIB_SYMBOL_VERSION@/$(DEFAULT_SYMBOL_VERSION)/'
+	sed <'$<' >'$@' -e 's/@JULIA_SHLIB_SYMBOL_VERSION@/JL_LIBJULIA_$(SOMAJOR)/'
 
 $(build_shlibdir)/libjulia-internal.$(JL_MAJOR_MINOR_SHLIB_EXT): $(BUILDDIR)/julia.expmap $(OBJS) $(BUILDDIR)/flisp/libflisp.a $(BUILDDIR)/support/libsupport.a $(LIBUV)
 	@$(call PRINT_LINK, $(CXXLD) $(call IMPLIB_FLAGS,$@) $(JCXXFLAGS) $(JL_CXXFLAGS) $(CXXLDFLAGS) $(SHIPFLAGS) $(OBJS) $(RPATH_LIB) -o $@ \