Fixed install instructions

INSTALL.txt

@@ -5,19 +5,19 @@ To compile and install SDL:
         * Read ./docs/README-visualc.md
 
         Windows building with mingw64 for x86:
-        * Run: cmake -S . -B build -DCMAKE_TOOLCHAIN_FILE=build-scripts/cmake-toolchain-mingw64-i686.cmake && cmake --build build && cmake --install install
+        * Run: cmake -S . -B build -DCMAKE_TOOLCHAIN_FILE=build-scripts/cmake-toolchain-mingw64-i686.cmake && cmake --build build && cmake --install build
 
         Windows building with mingw64 for x64:
-        * Run: cmake -S . -B build -DCMAKE_TOOLCHAIN_FILE=build-scripts/cmake-toolchain-mingw64-x86_64.cmake && cmake --build build && cmake --install install
+        * Run: cmake -S . -B build -DCMAKE_TOOLCHAIN_FILE=build-scripts/cmake-toolchain-mingw64-x86_64.cmake && cmake --build build && cmake --install build
 
         macOS with Xcode:
         * Read docs/README-macosx.md
 
         macOS from the command line:
-        * Run: cmake -S . -B build && cmake --build build && cmake --install install
+        * Run: cmake -S . -B build && cmake --build build && cmake --install build
 
         Linux and other UNIX systems:
-        * Run: cmake -S . -B build && cmake --build build && cmake --install install
+        * Run: cmake -S . -B build && cmake --build build && cmake --install build
 
         Android:
         * Read docs/README-android.md