drop unused HALIDE_PREFIX cmake variable

The include and library directories used to be derived from
this variable, but they have since been replaced in prehistory
by calls to find_path and find_library, with the first one
not using any path at all and the second one using
CMAKE_INSTALL_PREFIX, which has the same value as HALIDE_PREFIX.

Author: Sven Verdoolaege

CMakeLists.txt

@@ -155,10 +155,6 @@ endif()
 ################################################################################
 
 # Halide
-if(NOT HALIDE_PREFIX)
-  message(FATAL_ERROR "-DHALIDE_PREFIX=... required")
-endif()
-message(STATUS "HALIDE_PREFIX: ${HALIDE_PREFIX}")
 message(STATUS "Finding Halide")
 find_path(HALIDE_INCLUDE_DIR NAMES Halide.h)
 message(STATUS "HALIDE_INCLUDE_DIRS: ${HALIDE_INCLUDE_DIR}")

build.sh

@@ -404,7 +404,6 @@ function install_tc() {
         -DCMAKE_EXPORT_COMPILE_COMMANDS=ON \
         -DWITH_TAPIR=${WITH_TAPIR} \
         -DPYTHON_EXECUTABLE=${PYTHON} \
-        -DHALIDE_PREFIX=${INSTALL_PREFIX} \
         -DCMAKE_BUILD_TYPE=${BUILD_TYPE} \
         -DCMAKE_PREFIX_PATH=${INSTALL_PREFIX}/lib/cmake \
         -DCMAKE_INSTALL_PREFIX=${INSTALL_PREFIX} \