add static library prune utility (#1755)

tools/shell/prune_static_library.sh

+#!/bin/sh
+
+# Split all static libaries in the current directory into corresponding archtectures
+
+archs=(armv7 arm64)
+libraries=(*.a)
+libtool="/usr/bin/libtool"
+
+rm -rf tmp
+mkdir tmp
+
+echo "splitting and pruning ${libraries[*]}..."
+
+for library in ${libraries[*]}
+do
+    lipo -info $library
+    # Extract individual architectures for this library
+    for arch in ${archs[*]}
+    do
+        mkdir -p tmp/$arch
+        lipo -thin $arch $library -o ./tmp/$arch/${library}
+        cd tmp/$arch
+        ar x $library
+        rm $library
+        ar -rcs $library *.o
+        cd ../..
+    done
+done
+
+echo "joining static libriries..."
+cd tmp
+libtool -static -o $library armv7/$library arm64/$library
+
+# # split static library into objects
+# ar x 1.a
+# # join objects into static library
+# ar -rcs 2.a *.o
+# # join static libraries into one single static library
+# libtool -static -o 3.a 1.a 2.a
+# # list file by file size, prune according to file size
+# ls -Slhr directory