cmake: Fix find_program usage for 3.15

yuzu requires CMake 3.15 yet find_program was using REQUIRED, which is
only available on 3.18 and later. Instead, we check for
"<VAR>-NOTFOUND".

In addition, check for additional requirements before building libusb or
FFmpeg with autotools. Otherwise, CMake configuration will pass yet
compilation will fail.

1 files changed, 11 insertions, 0 deletions

diff --git a/externals/libusb/CMakeLists.txt b/externals/libusb/CMakeLists.txt
index 7180fd42a..9a30b1e2a 100644
--- a/externals/libusb/CMakeLists.txt
+++ b/externals/libusb/CMakeLists.txt
@@ -5,6 +5,17 @@ if (MINGW OR (${CMAKE_SYSTEM_NAME} MATCHES "Linux"))
     # GNU toolchains for some reason doesn't work with the later half of this CMakeLists after
     # updating to 1.0.24, so we do it the old-fashioned way for now.
 
+    # Require autoconf and libtoolize here, rather than crash during compilation
+    find_program(AUTOCONF autoconf)
+    if ("${AUTOCONF}" STREQUAL "AUTOCONF-NOTFOUND")
+        message(FATAL_ERROR "Required program `autoconf` not found.")
+    endif()
+
+    find_program(LIBTOOLIZE libtoolize)
+    if ("${LIBTOOLIZE}" STREQUAL "LIBTOOLIZE-NOTFOUND")
+        message(FATAL_ERROR "Required program `libtoolize` not found.")
+    endif()
+
     set(LIBUSB_PREFIX "${CMAKE_CURRENT_BINARY_DIR}/libusb")
     set(LIBUSB_SRC_DIR "${CMAKE_CURRENT_SOURCE_DIR}/libusb")