BLD Add DISTDIR variable. ### Description

Adds `DISTDIR` env variable that points to the directory where libraries should be copied to when building shared libraries with recipe.

### Checklists

- [x] Add new / update outdated documentation

package:
  name: libproj
  version: 8.2.1

source:
  sha256: 76ed3d0c3a348a6693dfae535e5658bbfd47f71cb7ff7eb96d9f12f7e068b1cf
  url: https://download.osgeo.org/proj/proj-8.2.1.tar.gz

requirements:
  host:
    - libtiff
  executable:
    - sqlite3

build:
  type: static_library
  script: |
    mkdir -p build

    embuilder build zlib --pic
    embuilder build sqlite3 --pic

    cd build \
        && LDFLAGS="-s NODERAWFS=1 -sFORCE_FILESYSTEM=1" emcmake cmake ../ \
        -DCMAKE_INSTALL_PREFIX=$WASM_LIBRARY_DIR \
        -DCMAKE_BUILD_TYPE=Release \
        -DENABLE_CURL=OFF \
        -DBUILD_APPS=OFF \
        -DBUILD_SHARED_LIBS=OFF \
        -DBUILD_TESTING=OFF \
        -DTIFF_INCLUDE_DIR=$WASM_LIBRARY_DIR/include \
        -DTIFF_LIBRARY=$WASM_LIBRARY_DIR/lib/libtiff.a \
        -DCMAKE_C_FLAGS="-fPIC" \
        -DCMAKE_CXX_FLAGS="-fPIC";
    emmake make -j ${PYODIDE_JOBS:-3} install;

package:
  name: libproj
  version: 8.2.1

source:
  sha256: 76ed3d0c3a348a6693dfae535e5658bbfd47f71cb7ff7eb96d9f12f7e068b1cf
  url: https://download.osgeo.org/proj/proj-8.2.1.tar.gz

requirements:
  host:
    - libtiff
  executable:
    - sqlite3

build:
  type: static_library
  script: |
    mkdir -p build

    embuilder build zlib --pic
    embuilder build sqlite3 --pic

    cd build \
        && LDFLAGS="-s NODERAWFS=1 -sFORCE_FILESYSTEM=1" emcmake cmake ../ \
        -DCMAKE_INSTALL_PREFIX=$WASM_LIBRARY_DIR \
        -DCMAKE_BUILD_TYPE=Release \
        -DENABLE_CURL=OFF \
        -DBUILD_APPS=OFF \
        -DBUILD_SHARED_LIBS=OFF \
        -DBUILD_TESTING=OFF \
        -DTIFF_INCLUDE_DIR=$WASM_LIBRARY_DIR/include \
        -DTIFF_LIBRARY=$WASM_LIBRARY_DIR/lib/libtiff.a \
        -DCMAKE_C_FLAGS="-fPIC" \
        -DCMAKE_CXX_FLAGS="-fPIC";
    emmake make -j ${PYODIDE_JOBS:-3} install;
