gentoo-overlay/dev-libs/snowball-stemmer/files/snowball-stemmer-2.2.0-shared-library.patch

This is based on a patch taken from alpinelinux, however, duplicated
libstemmer.o and stemwords targets were removed and the patch was
rebased on top of v2.2.0 tag.

Created shared library contains a lot of relocations, which slow down loading.
It is known issue and probably the main reason why upstream does not support
shared library yet [1].

[1] https://github.com/snowballstem/snowball/issues/34#issuecomment-203200078

Alpinelinux-patch: https://git.alpinelinux.org/aports/tree/community/snowball/libstemmer-library.patch?id=28f9d9e192876c43fd96bc5856cd9d8a50dd49c0
Upstream-issue: https://github.com/snowballstem/snowball/issues/34

diff --git a/GNUmakefile b/GNUmakefile
index 98eb1fa..9b539ec 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -4,6 +4,8 @@
 # which hard-code it.
 SNOWBALL_VERSION = 2.2.0
 
+MAJOR_VERSION := $(shell echo $(SNOWBALL_VERSION) | cut -d. -f1)
+
 ifeq ($(OS),Windows_NT)
 EXEEXT = .exe
 endif
@@ -170,12 +172,17 @@ C_OTHER_OBJECTS = $(C_OTHER_SOURCES:.c=.o)
 JAVA_CLASSES = $(JAVA_SOURCES:.java=.class)
 JAVA_RUNTIME_CLASSES=$(JAVARUNTIME_SOURCES:.java=.class)
 
-CFLAGS=-O2 -W -Wall -Wmissing-prototypes -Wmissing-declarations
-CPPFLAGS=
+CFLAGS+=-fPIC -W -Wall -Wmissing-prototypes -Wmissing-declarations
+CPPFLAGS+=
 
 INCLUDES=-Iinclude
 
-all: snowball$(EXEEXT) libstemmer.a stemwords$(EXEEXT) $(C_OTHER_SOURCES) $(C_OTHER_HEADERS) $(C_OTHER_OBJECTS)
+all: snowball$(EXEEXT) libstemmer.a libstemmer.so stemwords$(EXEEXT) $(C_OTHER_SOURCES) $(C_OTHER_HEADERS) $(C_OTHER_OBJECTS)
+
+libstemmer.so: libstemmer/libstemmer.o $(RUNTIME_OBJECTS) $(C_LIB_OBJECTS)
+	$(CC) $(CFLAGS) -shared $(LDFLAGS) -Wl,-soname,$@.$(MAJOR_VERSION),-version-script,libstemmer/symbol.map -o $@.$(SNOWBALL_VERSION) $^
+	ln -s $@.$(SNOWBALL_VERSION) $@.$(MAJOR_VERSION)
+	ln -s $@.$(SNOWBALL_VERSION) $@
 
 algorithms.mk: libstemmer/mkalgorithms.pl libstemmer/modules.txt
 	libstemmer/mkalgorithms.pl algorithms.mk libstemmer/modules.txt
diff --git a/libstemmer/symbol.map b/libstemmer/symbol.map
new file mode 100644
index 0000000..7a3d423
--- /dev/null
+++ b/libstemmer/symbol.map
@@ -0,0 +1,6 @@
+SB_STEMMER_0 {
+    global:
+        sb_stemmer_*;
+    local:
+        *;
+};