Add gdbm support (python 3.7)

Requires conda-forge/staged-recipes#6681

Author: hmaarrfk

recipe/meta.yaml

@@ -81,6 +81,7 @@ requirements:
     - {{ cdt('libx11-devel') }}          # [linux]
     - 7za               # [win]
     - curl              # [win]
+    - pkg-config        # [unix]
   host:
     - nasm 2.11.06      # [win]
     - bzip2             # [unix]
@@ -92,6 +93,7 @@ requirements:
     - zlib              # [unix]
     - ncurses           # [linux]
     - libffi            # [unix]
+    - gdbm              # [unix]
   run:
     - openssl           # [unix]
     - readline          # [unix]
@@ -104,6 +106,10 @@ requirements:
     #- vs2015_runtime    # [win]
 
 test:
+  requires:             # [unix]
+    - gdbm              # [unix]
+  imports:              # [unix]
+    - dbm.gnu           # [unix]
   commands:
     - python -V
     - python3 -V            # [unix]