From 0949c41dab340ff6bc3b18c3090238bd1f4f46b7 Mon Sep 17 00:00:00 2001
From: Sebastian Ehlert <2684096-awvwgk@users.noreply.gitlab.com>
Date: Sun, 11 Jul 2021 15:17:25 +0000
Subject: [PATCH] Use CMake's built-in zlib finder

---
 CMakeLists.txt              |  5 +++--
 cmake/FindStaticZLIB.cmake  | 12 ++++++++++++
 cmake/FindZLIB.cmake        | 14 --------------
 src/lfortran/CMakeLists.txt |  2 +-
 4 files changed, 16 insertions(+), 17 deletions(-)
 create mode 100644 cmake/FindStaticZLIB.cmake
 delete mode 100644 cmake/FindZLIB.cmake

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 44b001e11e..9aac58a9bf 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -77,8 +77,9 @@ set(LFORTRAN_STATIC_BIN no CACHE BOOL "Build LFortran as a static binary")
 set(WITH_LFORTRAN_BINARY_MODFILES YES
     CACHE BOOL "Use binary modfiles")
 
-#ZLIB
-find_package(ZLIB REQUIRED)
+# Find ZLIB with our custom finder before including LLVM since the finder for LLVM
+# might search for ZLIB again and find the shared libraries instead of the static ones
+find_package(StaticZLIB REQUIRED)
 
 # LLVM
 set(WITH_LLVM no CACHE BOOL "Build with LLVM support")
diff --git a/cmake/FindStaticZLIB.cmake b/cmake/FindStaticZLIB.cmake
new file mode 100644
index 0000000000..1467599800
--- /dev/null
+++ b/cmake/FindStaticZLIB.cmake
@@ -0,0 +1,12 @@
+# Backup the original value of the requested library suffixes
+set(_CMAKE_FIND_LIBRARY_SUFFIXES ${CMAKE_FIND_LIBRARY_SUFFIXES})
+# Static libraries end with .a on Unix and .lib on Windows
+set(CMAKE_FIND_LIBRARY_SUFFIXES .a .lib)
+
+# Now use CMake's built-in ZLIB finder
+find_package(ZLIB REQUIRED)
+
+# Reset the library suffixes to the original value
+set(CMAKE_FIND_LIBRARY_SUFFIXES ${_CMAKE_FIND_LIBRARY_SUFFIXES})
+# Unset the temporary to not pollute the global namespace
+unset(_CMAKE_FIND_LIBRARY_SUFFIXES)
diff --git a/cmake/FindZLIB.cmake b/cmake/FindZLIB.cmake
deleted file mode 100644
index fb6741a1b6..0000000000
--- a/cmake/FindZLIB.cmake
+++ /dev/null
@@ -1,14 +0,0 @@
-find_path(ZLIB_INCLUDE_DIR zlib.h)
-find_library(ZLIB_LIBRARY NAMES libz.a z)
-
-include(FindPackageHandleStandardArgs)
-find_package_handle_standard_args(ZLIB DEFAULT_MSG ZLIB_INCLUDE_DIR ZLIB_LIBRARY)
-
-add_library(p::zlib INTERFACE IMPORTED)
-set_property(TARGET p::zlib PROPERTY INTERFACE_INCLUDE_DIRECTORIES
-    ${ZLIB_INCLUDE_DIR})
-set_property(TARGET p::zlib PROPERTY INTERFACE_LINK_LIBRARIES
-    ${ZLIB_LIBRARY})
-
-message("ZLIB_INCLUDE_DIR: ${ZLIB_INCLUDE_DIR}")
-message("ZLIB_LIBRARY: ${ZLIB_LIBRARY}")
diff --git a/src/lfortran/CMakeLists.txt b/src/lfortran/CMakeLists.txt
index 79a99b9097..dc7b929655 100644
--- a/src/lfortran/CMakeLists.txt
+++ b/src/lfortran/CMakeLists.txt
@@ -72,7 +72,7 @@ if (WITH_LLVM)
     endif()
 endif()
 add_library(lfortran_lib ${SRC})
-target_link_libraries(lfortran_lib lfortran_runtime_static p::zlib)
+target_link_libraries(lfortran_lib lfortran_runtime_static ZLIB::ZLIB)
 target_include_directories(lfortran_lib BEFORE PUBLIC ${lfortran_SOURCE_DIR}/src)
 target_include_directories(lfortran_lib BEFORE PUBLIC ${lfortran_BINARY_DIR}/src)
 if (WITH_XEUS)