Problem: build fail without cgo

[yihuang]

Description

Support CGO_ENABLED=0 make build

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For contributor use:

• Targeted PR against correct branch (see CONTRIBUTING.md)
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the module structure standards.
• Wrote unit and integration tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Re-reviewed Files changed in the Github PR explorer

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For admin use:

• Added appropriate labels to PR (ex. WIP, R4R, docs, etc)
• Reviewers assigned
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 46.16%. Comparing base (ce5773e) to head (7f2d861).
Report is 1 commits behind head on develop.

Files with missing lines	Patch %	Lines
app/ante/eip712.go	50.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #549   +/-   ##
========================================
  Coverage    46.16%   46.16%           
========================================
  Files          181      181           
  Lines        18125    18125           
========================================
  Hits          8368     8368           
  Misses        9040     9040           
  Partials       717      717           

Files with missing lines	Coverage Δ
app/ante/eip712.go	59.42% <50.00%> (ø)