New freebsd platforms (#14801)

* add riscv as riscv64

* add all platforms supported by FreeBSD

compiler/installer.ini

@@ -9,7 +9,7 @@ Platforms: """
   linux: i386;hppa;ia64;alpha;amd64;powerpc64;arm;sparc;sparc64;m68k;mips;mipsel;mips64;mips64el;powerpc;powerpc64el;arm64;riscv64
   macosx: i386;amd64;powerpc64
   solaris: i386;amd64;sparc;sparc64
-  freebsd: i386;amd64;powerpc64;arm;arm64
+  freebsd: i386;amd64;powerpc64;arm;arm64;riscv64;sparc64;mips;mipsel;mips64;mips64el;powerpc
   netbsd: i386;amd64
   openbsd: i386;amd64;arm;arm64
   dragonfly: i386;amd64

tools/niminst/buildsh.nimf

@@ -185,7 +185,7 @@ case $ucpu in
     mycpu="arm64" ;;
   *arm*|*armv6l*|*armv71* )
     mycpu="arm" ;;
-  *riscv64* )
+  *riscv64|riscv* )
     mycpu="riscv64" ;;
   *)
     echo 2>&1 "Error: unknown processor: $ucpu"