Add WebP to build dependencies

Author: rodarima

.github/workflows/build.yml

@@ -10,7 +10,7 @@ jobs:
       with:
         fetch-depth: 1
     - name: Install dependencies
-      run: sudo apt install -y libfltk1.3-dev libssl-dev xvfb x11-apps x11-utils imagemagick
+      run: sudo apt install -y libfltk1.3-dev libssl-dev libwebp-dev xvfb x11-apps x11-utils imagemagick
 
     - name: autogen
       run: ./autogen.sh
@@ -164,6 +164,7 @@ jobs:
           fltk-dev
           libpng-dev
           libjpeg-turbo-dev
+          libwebp-dev
           mbedtls-dev
     - run: |
         ./autogen.sh
@@ -245,7 +246,7 @@ jobs:
         fetch-depth: 1
     - uses: cygwin/cygwin-install-action@master
       with:
-        packages: gcc-core gcc-g++ autoconf automake make zlib-devel mbedtls-devel libfltk-devel libiconv-devel libpng-devel libjpeg-devel libgif-devel
+        packages: gcc-core gcc-g++ autoconf automake make zlib-devel mbedtls-devel libfltk-devel libiconv-devel libpng-devel libjpeg-devel libwebp-devel libgif-devel
     - shell: C:\cygwin\bin\bash.exe --login --norc -eo pipefail -o igncr '{0}'
       run: |
         set -x

doc/install.md

@@ -35,7 +35,7 @@ packages to build Dillo:
 ```sh
 $ sudo apt install gcc g++ autoconf automake make zlib1g-dev \
     libfltk1.3-dev libssl-dev libc6-dev \
-    libpng-dev libjpeg-dev
+    libpng-dev libjpeg-dev libwebp-dev
 ```
 
 If you prefer to use mbedTLS, replace `libssl-dev` with
@@ -170,7 +170,7 @@ will need the following dependencies to build Dillo with mbedTLS:
 
 ```
 gcc-core gcc-g++ autoconf automake make zlib-devel mbedtls-devel libfltk-devel
-libiconv-devel libpng-devel libjpeg-devel
+libiconv-devel libpng-devel libjpeg-devel libwebp-devel
 ```
 
 **Note**: Dillo can also be built with OpenSSL (libssl-devel) but there is a
@@ -187,7 +187,7 @@ xorg-server xinit
 
 You can also install all the dependencies from the command line with:
 ```
-setup-x86_64.exe -q -P gcc-core,gcc-g++,autoconf,automake,make,zlib-devel,mbedtls-devel,libfltk-devel,libiconv-devel,libpng-devel,libjpeg-devel,xorg-server,xinit
+setup-x86_64.exe -q -P gcc-core,gcc-g++,autoconf,automake,make,zlib-devel,mbedtls-devel,libfltk-devel,libiconv-devel,libpng-devel,libjpeg-devel,libwebp-devel,xorg-server,xinit
 ```
 
 To build Dillo, follow the usual steps from a Cygwin shell: