Make IPASIR support compile

[tautschnig]

Hardness support was added to minisat2 only, and 89641a2 failed to
update the IPASIR interface.

Also cleanup the list of phony targets in the top-level Makefile, and
ensure that linking of the memory analyzer succeeds even in presence of
LIBS set on the make command line.

Fixes: #5345

• Each commit message has a non-empty body, explaining why the change was made.
• Methods or procedures I have added are documented, following the guidelines provided in CODING_STANDARD.md.
• n/a The feature or user visible behaviour I have added or modified has been documented in the User Guide in doc/cprover-manual/
• Regression or unit tests are included, or existing tests cover the modified code (in this case I have detailed which ones those are in the commit message).
• n/a My commit message includes data points confirming performance improvements (if claimed).
• My PR is restricted to a single feature or bugfix.
• n/a White-space or formatting changes outside the feature-related changed lines are in commits of their own.

[codecov]

Codecov Report

Merging #5549 (e5f4c93) into develop (bf62883) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop    #5549   +/-   ##
========================================
  Coverage    68.52%   68.52%           
========================================
  Files         1187     1187           
  Lines        98265    98265           
========================================
  Hits         67339    67339           
  Misses       30926    30926           

Flag	Coverage Δ
cproversmt2	42.96% <ø> (ø)
regression	65.68% <ø> (ø)
unit	32.26% <ø> (ø)

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