Add lmdb.pc for MacOS

Author: jasagredo

.github/workflows/haskell.yml

@@ -153,6 +153,8 @@ jobs:
       run: |
         brew install libsodium
         brew install lmdb
+        # LMDB is distributed without pkg-config file
+        cp $(pwd)/.github/workflows/lmdb.pc /usr/local/lib/pkgconfig/lmdb.pc
 
     - name: "MAC: Install build environment (secp256k1)"
       if: matrix.os == 'macos-latest'

.github/workflows/lmdb.pc

@@ -0,0 +1,11 @@
+prefix=/usr/local
+exec_prefix=${prefix}
+libdir=${exec_prefix}/lib
+includedir=${exec_prefix}/include
+
+Name: liblmdb
+Description: Lightning Memory-Mapped Database
+URL: https://symas.com/products/lightning-memory-mapped-database/
+Version: 0.9.29
+Libs: -L${libdir} -llmdb
+Cflags: -I${includedir}