This is based on a patch taken from alpinelinux, however, duplicated
libstemmer.o and stemwords targets were removed.

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 5cb2179..d1ef193 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -3,6 +3,7 @@
 # After changing this, run `make update_version` to update various sources
 # which hard-code it.
 SNOWBALL_VERSION = 2.1.0
+MAJOR_VERSION := $(shell echo $(SNOWBALL_VERSION) | cut -d. -f1)
 
 c_src_dir = src_c
 
@@ -162,10 +163,18 @@ 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=-Iinclude
+CFLAGS+=-fPIC -W -Wall -Wmissing-prototypes -Wmissing-declarations
+CPPFLAGS+=-Iinclude
 
-all: snowball libstemmer.o stemwords $(C_OTHER_SOURCES) $(C_OTHER_HEADERS) $(C_OTHER_OBJECTS)
+all: snowball libstemmer.o libstemmer.so libstemmer.a stemwords $(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) $@
+
+libstemmer.a: libstemmer.o
+	$(AR) -crs $@ $^
 
 clean:
 	rm -f $(COMPILER_OBJECTS) $(RUNTIME_OBJECTS) \
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:
+        *;
+};