Add support for SRFI 212

Closes #646

doc/reference/srfi/README.md

@@ -63,3 +63,4 @@ The following SRFIs are supported by gerbil:
 | [SRFI 158](https://srfi.schemers.org/srfi-158/srfi-158.html) | Generators and Accumulators                            | stdlib       | `:std/srfi/158`           |
 | [SRFI 159](https://srfi.schemers.org/srfi-159/srfi-159.html) | Combinator Formatting                                  | stdlib       | `:std/srfi/159`           |
 | [SRFI 160](https://srfi.schemers.org/srfi-160/srfi-160.html) | Homogeneous Numeric Vector Libraries                   | stdlib       | `:std/srfi/160/{lib}` for `base`, `u8`, `s8`, `u16`, `s16`, `u32`, `s32`, `u64`, `s64`, `f32`, `f64`, `c64`, `c128` |
+| [SRFI 212](https://srfi.schemers.org/srfi-212/srfi-212.html) | Aliases                                  | stdlib       | `:std/srfi/212`           |

src/srfi/212.ss

@@ -0,0 +1 @@
+(import :std/srfi/212) (export (import: :std/srfi/212))

src/srfi/build.ss

@@ -41,7 +41,8 @@
           146
           151
           158
-          159))
+          159
+          212))
    (map (srfi-package "146/")
         '(hamt hamt-map hamt-misc hash vector-edit))
    (map (srfi-package "159/")

src/std/build-spec.ss

@@ -155,6 +155,7 @@
     "srfi/160/f64"
     "srfi/160/c64"
     "srfi/160/c128"
+    "srfi/212"
     ;; :std/parser
     "parser/rlang"
     "parser/base"

src/std/srfi/212.ss

@@ -0,0 +1 @@
+(export (rename: defalias alias))