Compile time let and var aliases to compile time functions fail.

[deech]

The following fails with:

/usr/bin/ld: /home/deech/.cache/nim/constproc_d/constproc.c.o: in function `NimMainModule':
constproc.c:(.text+0x284): undefined reference to `f_bfa0L49aD5jfHWe71uFSAuw'
collect2: error: ld returned 1 exit status
Error: execution of an external program failed: 'gcc   -o /home/deech/Nim/constproc  /home/deech/.cache/nim/constproc_d/stdlib_io.c.o /home/deech/.cache/nim/constproc_d/stdlib_system.c.o /home/deech/.cache/nim/constproc_d/constproc.c.o    -ldl'

proc foo(): int {.compileTime.} = 100
var f {.compileTime.} = foo
echo f()

Change var to let and you get the same thing.

[krux02]

workaround:

proc foo(): int {.compileTime.} = 100
var f {.compileTime.} = foo
static:
  echo f()

[mratsim]

Duplicate #9970, #10990 and #10962