cmake: LLVM needs to link against zlib

For more details on why this dependency is needed, see
ziglang/zig-bootstrap#57

Author: andrewrk

CMakeLists.txt

@@ -67,6 +67,7 @@ message("Configuring zig version ${ZIG_VERSION}")
 
 set(ZIG_STATIC off CACHE BOOL "Attempt to build a static zig executable (not compatible with glibc)")
 set(ZIG_STATIC_LLVM off CACHE BOOL "Prefer linking against static LLVM libraries")
+set(ZIG_STATIC_ZLIB off CACHE BOOL "Prefer linking against static zlib")
 set(ZIG_PREFER_CLANG_CPP_DYLIB off CACHE BOOL "Try to link against -lclang-cpp")
 set(ZIG_USE_CCACHE off CACHE BOOL "Use ccache if available")
 
@@ -75,7 +76,8 @@ if(CCACHE_PROGRAM AND ZIG_USE_CCACHE)
 endif()
 
 if(ZIG_STATIC)
-    set(ZIG_STATIC_LLVM "on")
+    set(ZIG_STATIC_LLVM ON)
+    set(ZIG_STATIC_ZLIB ON)
 endif()
 
 string(REGEX REPLACE "\\\\" "\\\\\\\\" ZIG_LIBC_LIB_DIR_ESCAPED "${ZIG_LIBC_LIB_DIR}")
@@ -101,11 +103,13 @@ find_package(llvm)
 find_package(clang)
 find_package(lld)
 
-if(APPLE AND ZIG_STATIC)
+if(ZIG_STATIC_ZLIB)
     list(REMOVE_ITEM LLVM_LIBRARIES "-lz")
-    find_library(ZLIB NAMES libz.a z zlib libz)
+    find_library(ZLIB NAMES libz.a libzlibstatic.a z zlib libz)
     list(APPEND LLVM_LIBRARIES "${ZLIB}")
+endif()
 
+if(APPLE AND ZIG_STATIC)
     list(REMOVE_ITEM LLVM_LIBRARIES "-lcurses")
     find_library(CURSES NAMES libcurses.a curses libcurses libncurses.a ncurses libncurses)
     list(APPEND LLVM_LIBRARIES "${CURSES}")