build: Describe --nm and -ld options consistently

Signed-off-by: Alexander Strasser <eclipse7@gmx.net>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

configure

@@ -218,13 +218,13 @@ Advanced options (experts only):
   --target-os=OS           compiler targets OS [$target_os]
   --target-exec=CMD        command to run executables on target
   --target-path=DIR        path to view of build directory on target
-  --nm=NM                  use nm tool
+  --nm=NM                  use nm tool NM [$nm_default]
   --ar=AR                  use archive tool AR [$ar_default]
   --as=AS                  use assembler AS [$as_default]
   --yasmexe=EXE            use yasm-compatible assembler EXE [$yasmexe_default]
   --cc=CC                  use C compiler CC [$cc_default]
   --cxx=CXX                use C compiler CXX [$cxx_default]
-  --ld=LD                  use linker LD
+  --ld=LD                  use linker LD [$ld_default]
   --host-cc=HOSTCC         use host C compiler HOSTCC
   --host-cflags=HCFLAGS    use HCFLAGS when compiling for host
   --host-ldflags=HLDFLAGS  use HLDFLAGS when linking for host