Add dependencies to run and generation targets

The CMake targets that run QEMU now depend on the targets
that generate the corresponding boot media, if it exists.

The targets that generate boot media now rely on their dependencies, as well.

README.md

@@ -209,6 +209,8 @@ Here is a list of the current build targets relating to boot media
   generation, as well as their dependencies listed underneath each.
 - `image_raw` --
   Combine built executables and resources to generate UEFI-compatible FAT32 boot media.
+  - `Kernel` build target (creates `kernel/bin/kernel.elf`).
+  - The built bootloader EFI application at `gnu-efi/x86_64/bootloader/main.efi`.
   - dd -- Native command on Unix
     - On Windows, use one of the following options:
       - [MinGW installer to get MSYS coreutils ext package](https://osdn.net/projects/mingw/)
@@ -234,11 +236,16 @@ Here is a list of the current build targets relating to boot media
     - Debian distros: `sudo apt install xorriso`
     - [Pre-built binaries for Windows](https://github.com/PeyTy/xorriso-exe-for-windows)
 
-The generated targets can be chained together for easy, quick development. \
-To build the LensorOS kernel, generate new boot media, and then
-  launch into LensorOS, it takes just one command.
-```bash
-cmake --build kernel/bld  && cmake --build kernel/bld -t image_raw runimg_qemu
+As an example, a FAT32 formatted UEFI-compatible boot
+  image may be generated using the following command:
+```sh
+cmake --build kernel/bld --target image_raw
+```
+
+It takes just one command to build the LensorOS kernel, generate new
+  boot media, and then launch the QEMU virtual machine into LensorOS.
+```sh
+cmake --build kernel/bld --target runimg_qemu
 ```
 
 ---

kernel/CMakeLists.txt

@@ -165,10 +165,14 @@ if( CMAKE_HOST_UNIX AND BASH_PROGRAM )
       image_raw
       COMMAND bash mkimg.sh
       WORKING_DIRECTORY ${SCRIPTS_DIR}
+      DEPENDS
+      ${REPO_DIR}/gnu-efi/x86_64/bootloader/main.efi
+      ${SCRIPTS_DIR}/startup.nsh
       COMMENT "Generating UEFI-compatible FAT32 boot media"
       USES_TERMINAL
       VERBATIM
     )
+    add_dependencies( image_raw Kernel )
   endif()
   # Boot media generation: GPT partitioned hard drive.
   if( FDISK_PROGRAM )
@@ -203,6 +207,9 @@ if( CMAKE_HOST_UNIX AND BASH_PROGRAM )
       "   Install mkgpt using ${SCRIPTS_DIR}/install_mkgpt.sh"
     )
   endif()
+  if( TARGET image_gpt AND TARGET image_raw )
+    add_dependencies( image_gpt image_raw )
+  endif()
   # Boot media generation: ISO-9660 CD-ROM.
   if( XORRISO_PROGRAM )
     message(
@@ -217,6 +224,9 @@ if( CMAKE_HOST_UNIX AND BASH_PROGRAM )
       USES_TERMINAL
       VERBATIM
     )
+    if( TARGET image_raw )
+      add_dependencies( image_iso image_raw )
+    endif()
   else()
     message( "-- xorriso was not found on your system, skipping image_iso target generation." )
   endif()
@@ -235,9 +245,14 @@ if( CMAKE_HOST_WIN32 )
       image_raw
       COMMAND cmd /c ${SCRIPTS_DIR}/mkimg.bat
       COMMENT "Generating UEFI-compatible FAT32 boot media"
+      DEPENDS
+      ${REPO_DIR}/gnu-efi/x86_64/bootloader/main.efi
+      ${SCRIPTS_DIR}/startup.nsh
       USES_TERMINAL
       VERBATIM
     )
+    # Image generation relies on kernel.elf
+    add_dependencies( image_raw Kernel )
   endif()
   # Boot media generation: ISO-9660 CD-ROM.
   if( XORRISO_PROGRAM )
@@ -252,6 +267,9 @@ if( CMAKE_HOST_WIN32 )
       USES_TERMINAL
       VERBATIM
     )
+    if( TARGET image_raw )
+      add_dependencies( image_iso image_raw )
+    endif()
   else()
     message( "-- xorriso was not found on your system, skipping image_iso target generation." )
   endif()
@@ -344,4 +362,14 @@ if ( QEMU_PROGRAM )
     WORKING_DIRECTORY ${REPO_DIR}
     VERBATIM
   )
-endif ()
+  # Dependencies
+  if( TARGET image_raw )
+    add_dependencies( runimg_qemu image_raw )
+  endif()
+  if( TARGET image_gpt )
+    add_dependencies( runhda_qemu image_gpt )
+  endif()
+  if( TARGET image_iso )
+    add_dependencies( runiso_qemu image_iso )
+  endif()
+endif()