fix MinGW build　@Pete Batard

• Use the SIZEOF() macro in ldscript, to find if a section is empty or not defined.
• Ensure that -fno-asynchronous-unwind-tables is used when checking objcopy behaviour,
  by setting CPPFLAGS in configure.ac. Without this, the objcopy absolute address test
  fails because gcc on MinGW creates a .eh_frame section, that objcopy can’t handle.
• Note: To get a working grub4dos using MinGW, you may have to downgrade gcc to 4.6.2 using:
  mingw-get upgrade gcc=4.6.2-1
  mingw-get install mpc=0.8.1-1
  You should also run autogen.sh or bootstrap.sh before invoking configure.

fix MinGW build　@Pete Batard

• Use the SIZEOF() macro in ldscript, to find if a section is empty or not defined.
• Ensure that -fno-asynchronous-unwind-tables is used when checking objcopy behaviour,
  by setting CPPFLAGS in configure.ac. Without this, the objcopy absolute address test
  fails because gcc on MinGW creates a .eh_frame section, that objcopy can’t handle.
• Note: To get a working grub4dos using MinGW, you may have to downgrade gcc to 4.6.2 using:
  mingw-get upgrade gcc=4.6.2-1
  mingw-get install mpc=0.8.1-1
  You should also run autogen.sh or bootstrap.sh before invoking configure.

修正(md,BASE,SIZE)的BUG　@chenall

delmod -l XXX 改成返回该模块所在内存的起始位置.

修正(md,BASE,SIZE)的BUG　@chenall

delmod -l XXX 改成返回该模块所在内存的起始位置.

add autogen/bootstrap　@Pete Batard

• This makes it more convenient to invoke autotools. Also MinGW users
  may need to run one of these scripts to be able to compile.

• enable silent rules when building　@Pete Batard

• Note: ONLY configure.ac and stage2/Makefile.am were manually modified.
  The other files were generated by autotools.

• fix assembler warnings　@Pete Batard

• dosstart.S:1356: Warning: using %ax' instead of%eax’ due to `w’ suffix

• grldrstart.S:1277: Warning: using %ax' instead of%eax’ due to `w’ suffix

• fix 2 compiler warnings　@Pete Batard

• char_io.c:283:7: warning: pointer targets in assignment differ in signedness

• fsys_initrd.c:56:13: warning: initialization makes pointer from integer without a cast

add autogen/bootstrap　@Pete Batard

• This makes it more convenient to invoke autotools. Also MinGW users
  may need to run one of these scripts to be able to compile.

• enable silent rules when building　@Pete Batard

• Note: ONLY configure.ac and stage2/Makefile.am were manually modified.
  The other files were generated by autotools.

• fix assembler warnings　@Pete Batard

• dosstart.S:1356: Warning: using %ax' instead of%eax’ due to `w’ suffix

• grldrstart.S:1277: Warning: using %ax' instead of%eax’ due to `w’ suffix

• fix 2 compiler warnings　@Pete Batard

• char_io.c:283:7: warning: pointer targets in assignment differ in signedness

• fsys_initrd.c:56:13: warning: initialization makes pointer from integer without a cast

支持直访问某个内存区域(md,BASE,SIZE),以字节为单位.　@chenall

比如在内存块0x887700长度0x51200是一个软盘镜像,则可以使用如下方式快速访问

ls (md,0x887700,0x51200)/

如果是硬盘镜像,也可以直接访问硬盘分区.
ls (md,0x887700,0x51200,0)/