crt: Need a position-independent CRT for PIE
- Implement the greatest possible part of the crt1 in C
- Implement SPARC versions of the ASM sections of crt1
- Build crt1 position-independently, minor ASM updates to be position
  independent
- Implement crt1 with the hook expected by modern GCC to support
  profiling, make gcrt1 a symlink for source compatibility (older GCC
  initializes profiling at firsnt use of _mcount if necessary, so
  doesn't need the gcrt)
- Split the CRT out of developer/library/lint into a separate c-runtime package

*** 41,51 ****
  # interdependencies" below.
  .PARALLEL:
  
  # Build libc and its dependencies
  SUBDIRS=                        \
!         common                  \
          ../cmd/sgs/libconv      \
          ../cmd/sgs/libdl        \
          libc                    \
          .WAIT
  
--- 41,51 ----
  # interdependencies" below.
  .PARALLEL:
  
  # Build libc and its dependencies
  SUBDIRS=                        \
!         crt                     \
          ../cmd/sgs/libconv      \
          ../cmd/sgs/libdl        \
          libc                    \
          .WAIT
  
*** 548,559 ****
  _msg:                   $(MSGSUBDIRS:%=%-nodepend) .WAIT _dc
  
  _dc:                    $(DCSUBDIRS:%=%-nodepend)
  
  # Library interdependencies are called out explicitly here.
! ../cmd/sgs/libconv: common
! ../cmd/sgs/libdl: common
  libc:           ../cmd/sgs/libconv ../cmd/sgs/libdl
  
  libm:           libc
  libmd:          libc
  libmp:          libc
--- 548,559 ----
  _msg:                   $(MSGSUBDIRS:%=%-nodepend) .WAIT _dc
  
  _dc:                    $(DCSUBDIRS:%=%-nodepend)
  
  # Library interdependencies are called out explicitly here.
! ../cmd/sgs/libconv: crt
! ../cmd/sgs/libdl: crt
  libc:           ../cmd/sgs/libconv ../cmd/sgs/libdl
  
  libm:           libc
  libmd:          libc
  libmp:          libc