Dynamically link compiler executable.

DDlog used to rely on static linking to reduce runtime dependencies.
Unfortunately, this no longer works well on recent Ubuntu and Fedora
releases (see vmware#1051).  The problem appears to be in the `unix` Haskell
package, which may still load dynamic libraries (in particular glibc)
using `dlopen` when using static linking.  As far as I can tell it uses
older versions of Linux static libraries, which require some deprecated
libc symbols (specifically `__xmnod`).  This will probably get fixed
eventually, but overall static linking probably was not a good idea, so
we switch to the more standard dynamic linking method.

README.md

@@ -129,15 +129,6 @@ You are now ready to [start coding in DDlog](doc/tutorial/tutorial.md).
   export PATH=`pwd`:$PATH
   cd ..
   ```
-- Static versions of the following libraries: `libpthread.a`, `libc.a`, `libm.a`, `librt.a`, `libutil.a`,
-  `libdl.a`, `libgmp.a`, and `libstdc++.a` can be installed from distro-specific packages.  On Ubuntu:
-  ```
-  apt install libc6-dev libgmp-dev
-  ```
-  On Fedora:
-  ```
-  dnf install glibc-static gmp-static libstdc++-static
-  ```
 
 #### Building
 

package.yaml

@@ -48,7 +48,7 @@ dependencies:
 library:
   source-dirs: src
   ghc-options:
-  - -optl-static
+  # - -optl-static
   - -optl-pthread
   - -Wall
   - -Werror
@@ -66,7 +66,7 @@ executables:
               - -threaded
               - -rtsopts
               - -with-rtsopts=-N
-              - -optl-static
+              # - -optl-static
               - -optl-pthread
               - -Wall
               - -Werror
@@ -91,7 +91,7 @@ executables:
               - -threaded
               - -rtsopts
               - -with-rtsopts=-N
-              - -optl-static
+              # - -optl-static
               - -Wall
               - -Werror
       else: